[Codelab Issue] Testing Codelab 5.1, Step 4 - SnackBar not Shown

[sku0x20]

Describe the problem
SnackBar is not shown after checkbox of Tasks is checked or unchecked in the TasksFragment fragment. It happens after clicking the Tasks items from the tasklist to open TaskDetailFragment fragment and then pressing back or up to get back to TasksFragment screen.
I have not checked the end code or other branch then starter_code but I think this bug will be there.

In which lesson and step of the codelab can this issue be found?
Lesson 5.1 step 3

How to reproduce?

1. Open the Todo app.
2. Click any item from the two items already in the tasks list.
3. Press back or up
4. Now try to check checkbox.

Versions
4.0

Additional information
I have tested this on android 10 emulator running on ubuntu

codelab: advanced-android-kotlin

[JoseAlcerreca]

I can reproduce this