[Edge] Incorrect mutations are fired for backspace

[Reinmar]

1. Go to http://localhost:8125/ckeditor5-engine/tests/view/manual/mutationobserver.html
2. Place the caret at the beginning of the second paragraph.
3. Press backspace.

Error is thrown:

It's most likely caused by incorrect mutations:

[Reinmar]

@Mgsy could you check if it's still happening?

[Mgsy]

Unfortunately, I'm still able to reproduce it.

[CKEditorBot]

There has been no activity on this issue for the past year. We've marked it as stale and will close it in 30 days. We understand it may be relevant, so if you're interested in the solution, leave a comment or reaction under this issue.

[CKEditorBot]

We've closed your issue due to inactivity over the last year. We understand that the issue may still be relevant. If so, feel free to open a new one (and link this issue to it).