diff --git a/lib/document.js b/lib/document.js
index 81d51a2ce3e..0918d26fbff 100644
--- a/lib/document.js
+++ b/lib/document.js
@@ -2684,7 +2684,7 @@ function _getPathsToValidate(doc, pathsToValidate, pathsToSkip) {
 
     // Optimization: if primitive path with no validators, or array of primitives
     // with no validators, skip validating this path entirely.
-    if (!_pathType.caster && _pathType.validators.length === 0) {
+    if (!_pathType.caster && _pathType.validators.length === 0 && !_pathType.$parentSchemaDocArray) {
       paths.delete(path);
     } else if (_pathType.$isMongooseArray &&
       !_pathType.$isMongooseDocumentArray && // Skip document arrays...
@@ -2771,7 +2771,19 @@ function _getPathsToValidate(doc, pathsToValidate, pathsToSkip) {
 
   for (const path of paths) {
     const _pathType = doc.$__schema.path(path);
-    if (!_pathType || !_pathType.$isSchemaMap) {
+
+    if (!_pathType) {
+      continue;
+    }
+
+    // If underneath a document array, may need to re-validate the parent
+    // array re: gh-6818. Do this _after_ adding subpaths, because
+    // we don't want to add every array subpath.
+    if (_pathType.$parentSchemaDocArray && typeof _pathType.$parentSchemaDocArray.path === 'string') {
+      paths.add(_pathType.$parentSchemaDocArray.path);
+    }
+
+    if (!_pathType.$isSchemaMap) {
       continue;
     }
 
@@ -3318,14 +3330,7 @@ Document.prototype.$__reset = function reset() {
     if (this.isModified(fullPathWithIndexes) || isParentInit(fullPathWithIndexes)) {
       subdoc.$__reset();
       if (subdoc.$isDocumentArrayElement) {
-        if (!resetArrays.has(subdoc.parentArray())) {
-          const array = subdoc.parentArray();
-          this.$__.activePaths.clearPath(fullPathWithIndexes.replace(/\.\d+$/, '').slice(-subdoc.$basePath - 1));
-          array[arrayAtomicsBackupSymbol] = array[arrayAtomicsSymbol];
-          array[arrayAtomicsSymbol] = {};
-
-          resetArrays.add(array);
-        }
+        resetArrays.add(subdoc.parentArray());
       } else {
         if (subdoc.$parent() === this) {
           this.$__.activePaths.clearPath(subdoc.$basePath);
@@ -3338,6 +3343,12 @@ Document.prototype.$__reset = function reset() {
     }
   }
 
+  for (const array of resetArrays) {
+    this.$__.activePaths.clearPath(array.$path());
+    array[arrayAtomicsBackupSymbol] = array[arrayAtomicsSymbol];
+    array[arrayAtomicsSymbol] = {};
+  }
+
   function isParentInit(path) {
     path = path.indexOf('.') === -1 ? [path] : path.split('.');
     let cur = '';
diff --git a/lib/helpers/populate/getModelsMapForPopulate.js b/lib/helpers/populate/getModelsMapForPopulate.js
index 314661ff2e3..dd70d436203 100644
--- a/lib/helpers/populate/getModelsMapForPopulate.js
+++ b/lib/helpers/populate/getModelsMapForPopulate.js
@@ -64,7 +64,7 @@ module.exports = function getModelsMapForPopulate(model, docs, options) {
         schema.options.refPath == null) {
       continue;
     }
-    const isUnderneathDocArray = schema && schema.$isUnderneathDocArray;
+    const isUnderneathDocArray = schema && schema.$parentSchemaDocArray;
     if (isUnderneathDocArray && get(options, 'options.sort') != null) {
       return new MongooseError('Cannot populate with `sort` on path ' + options.path +
         ' because it is a subproperty of a document array');
diff --git a/lib/helpers/populate/getSchemaTypes.js b/lib/helpers/populate/getSchemaTypes.js
index 0534f015286..8cbbcafa8b1 100644
--- a/lib/helpers/populate/getSchemaTypes.js
+++ b/lib/helpers/populate/getSchemaTypes.js
@@ -101,8 +101,8 @@ module.exports = function getSchemaTypes(model, schema, doc, path) {
               nestedPath.concat(parts.slice(0, p))
             );
             if (ret) {
-              ret.$isUnderneathDocArray = ret.$isUnderneathDocArray ||
-                !foundschema.schema.$isSingleNested;
+              ret.$parentSchemaDocArray = ret.$parentSchemaDocArray ||
+                (foundschema.schema.$isSingleNested ? null : foundschema);
             }
             return ret;
           }
@@ -117,10 +117,10 @@ module.exports = function getSchemaTypes(model, schema, doc, path) {
                 nestedPath.concat(parts.slice(0, p))
               );
               if (_ret != null) {
-                _ret.$isUnderneathDocArray = _ret.$isUnderneathDocArray ||
-                  !foundschema.schema.$isSingleNested;
-                if (_ret.$isUnderneathDocArray) {
-                  ret.$isUnderneathDocArray = true;
+                _ret.$parentSchemaDocArray = _ret.$parentSchemaDocArray ||
+                  (foundschema.schema.$isSingleNested ? null : foundschema);
+                if (_ret.$parentSchemaDocArray) {
+                  ret.$parentSchemaDocArray = _ret.$parentSchemaDocArray;
                 }
                 ret.push(_ret);
               }
@@ -135,8 +135,8 @@ module.exports = function getSchemaTypes(model, schema, doc, path) {
             );
 
             if (ret) {
-              ret.$isUnderneathDocArray = ret.$isUnderneathDocArray ||
-                !foundschema.schema.$isSingleNested;
+              ret.$parentSchemaDocArray = ret.$parentSchemaDocArray ||
+                (foundschema.schema.$isSingleNested ? null : foundschema);
             }
             return ret;
           }
@@ -188,10 +188,6 @@ module.exports = function getSchemaTypes(model, schema, doc, path) {
             nestedPath.concat(parts.slice(0, p))
           );
 
-          if (ret) {
-            ret.$isUnderneathDocArray = ret.$isUnderneathDocArray ||
-              !model.schema.$isSingleNested;
-          }
           return ret;
         }
       }
@@ -212,8 +208,8 @@ module.exports = function getSchemaTypes(model, schema, doc, path) {
           );
 
           if (ret != null) {
-            ret.$isUnderneathDocArray = ret.$isUnderneathDocArray ||
-              !schema.$isSingleNested;
+            ret.$parentSchemaDocArray = ret.$parentSchemaDocArray ||
+              (schema.$isSingleNested ? null : schema);
             return ret;
           }
         }
diff --git a/lib/schema.js b/lib/schema.js
index 0269d1bc0f7..eb3f79feea6 100644
--- a/lib/schema.js
+++ b/lib/schema.js
@@ -1131,22 +1131,22 @@ Schema.prototype.path = function(path, obj) {
     for (const key of Object.keys(schemaType.schema.paths)) {
       const _schemaType = schemaType.schema.paths[key];
       this.subpaths[path + '.' + key] = _schemaType;
-      if (typeof _schemaType === 'object' && _schemaType != null) {
-        _schemaType.$isUnderneathDocArray = true;
+      if (typeof _schemaType === 'object' && _schemaType != null && _schemaType.$parentSchemaDocArray == null) {
+        _schemaType.$parentSchemaDocArray = schemaType;
       }
     }
     for (const key of Object.keys(schemaType.schema.subpaths)) {
       const _schemaType = schemaType.schema.subpaths[key];
       this.subpaths[path + '.' + key] = _schemaType;
-      if (typeof _schemaType === 'object' && _schemaType != null) {
-        _schemaType.$isUnderneathDocArray = true;
+      if (typeof _schemaType === 'object' && _schemaType != null && _schemaType.$parentSchemaDocArray == null) {
+        _schemaType.$parentSchemaDocArray = schemaType;
       }
     }
     for (const key of Object.keys(schemaType.schema.singleNestedPaths)) {
       const _schemaType = schemaType.schema.singleNestedPaths[key];
       this.subpaths[path + '.' + key] = _schemaType;
-      if (typeof _schemaType === 'object' && _schemaType != null) {
-        _schemaType.$isUnderneathDocArray = true;
+      if (typeof _schemaType === 'object' && _schemaType != null && _schemaType.$parentSchemaDocArray == null) {
+        _schemaType.$parentSchemaDocArray = schemaType;
       }
     }
   }
@@ -2556,16 +2556,16 @@ Schema.prototype._getSchema = function(path) {
                 // comments.$.comments.$.title
                 ret = search(parts.slice(p + 1), foundschema.schema);
                 if (ret) {
-                  ret.$isUnderneathDocArray = ret.$isUnderneathDocArray ||
-                    !foundschema.schema.$isSingleNested;
+                  ret.$parentSchemaDocArray = ret.$parentSchemaDocArray ||
+                    (foundschema.schema.$isSingleNested ? null : foundschema);
                 }
                 return ret;
               }
               // this is the last path of the selector
               ret = search(parts.slice(p), foundschema.schema);
               if (ret) {
-                ret.$isUnderneathDocArray = ret.$isUnderneathDocArray ||
-                  !foundschema.schema.$isSingleNested;
+                ret.$parentSchemaDocArray = ret.$parentSchemaDocArray ||
+                  (foundschema.schema.$isSingleNested ? null : foundschema);
               }
               return ret;
             }
diff --git a/test/document.test.js b/test/document.test.js
index 1e6c9ef7afd..2e7f2fb5fcf 100644
--- a/test/document.test.js
+++ b/test/document.test.js
@@ -6285,7 +6285,9 @@ describe('document', function() {
             name: String,
             folders: {
               type: [{ folderId: String }],
-              validate: v => assert.ok(v.length === new Set(v.map(el => el.folderId)).size, 'Duplicate')
+              validate: v => {
+                assert.ok(v.length === new Set(v.map(el => el.folderId)).size, 'Duplicate');
+              }
             }
           }]
         }
@@ -12212,6 +12214,25 @@ describe('document', function() {
     const fromDb = await Test.findById(x._id).lean();
     assert.equal(fromDb.c.x.y, 1);
   });
+
+  it('cleans up all array subdocs modified state on save (gh-13582)', async function() {
+    const ElementSchema = new mongoose.Schema({
+      elementName: String
+    });
+
+    const MyDocSchema = new mongoose.Schema({
+      docName: String,
+      elements: [ElementSchema]
+    });
+
+    const Test = db.model('Test', MyDocSchema);
+    let doc = new Test({ docName: 'MyDocName' });
+    doc.elements.push({ elementName: 'ElementName1' });
+    doc.elements.push({ elementName: 'ElementName2' });
+    doc = await doc.save();
+    assert.deepStrictEqual(doc.elements[0].modifiedPaths(), []);
+    assert.deepStrictEqual(doc.elements[1].modifiedPaths(), []);
+  });
 });
 
 describe('Check if instance function that is supplied in schema option is availabe', function() {