Markdown editor: unordered task list item forces its children to also be unordered

Summary

In the markdown editor (issues, merge requests etc.) a nested ordered task list is rendered as an unordered task list when at least one of its parents is an unordered task list.

Steps to reproduce

Inside the Markdown editor

Example

- [x] outer ul
    1. [x] a
    2. [ ] b
        1. [ ] x
        2. [x] y

Result:

• outer ul
  1. a
  2. b
     1. x
     2. y

Another example

1. [ ] outer ol
    - [x] a
    - [ ] b
        1. [ ] x
        2. [x] y

Result

1. outer ol
   • a
   • b
     1. x
     2. y

What is the current bug behavior?

ordered task list items are rendered as unordered task list items, depending on their parents.

In the first example the task list items a, b, x and y are rendered as unordered although they are defined as ordered task list items.

In the second example the task list items x and y are rendered as unordered although they are defined as ordered task list items.

Interestingly an ordered parent does not force its children to become ordered. A normal (not a task list) item parent also does not interfere with its children.

What is the expected correct behavior?

Task list items should be rendered as unordered if and only if they themselves are defined as unordered. The rendering should not depend on their parents.

For the first example:

And the second:

Output of checks

This bug happens on GitLab.com e.g. when writing this issue