Nested lists indentation error

[cmsirbu]

It looks like when encountering a list within a list, yamllint expects an extra level of indentation. I'm running version 1.35.1. Here's an example which, according to the documentation, should pass.

.yamllint.yaml

---
extends: "default"
rules:
  indentation:
    spaces: 2
    indent-sequences: true

issue.yaml

---
- flying:
  - spaghetti
  - monster
- not flying:
  - spaghetti
  - sauce

Output:

> uv run yamllint issue.yaml 
issue.yaml
  3:3       error    wrong indentation: expected 4 but found 2  (indentation)
  6:3       error    wrong indentation: expected 4 but found 2  (indentation)

---

I'm encountering this when parsing mkdocs configuration, where it's quite common to have lists within lists in the nav section:

nav:
  - Home: index.md
  - User Guide:
    - Writing your docs: writing-your-docs.md
    - Styling your docs: styling-your-docs.md
  - About:
    - License: license.md
    - Release Notes: release-notes.md

To me 2 spaces for each list level seems natural (and sufficient), but I can't find examples in the latest yaml spec itself.

[0phoff]

I am encountering the exact same issue.
Quote annoying as it breaks my CI/CD