Up/down keyboard navigation occasionally gets stuck

[mcsf]

See also: #44753

Description

Keyboard movement occasionally breaks for no apparent reason. In certain circumstances, pressing the Up and Down keys to navigate across blocks stops working, with the caret seemingly stuck until pointer intervention.

Of all the browsers, Safari seems to be the worst affected here.

Step-by-step reproduction instructions

(See screencast below.)

Screenshots, screen recording, code snippet

In the following screencast, I just keep pressing Up until the caret gets stuck. In this case, it got stuck on the large-text paragraph, but it can get stuck anywhere. You can't tell, but I am pressing Up at that point. The only way to unstick it is to use the cursor to scroll up a little, and then the caret can resume:

stuck-safari.mov

Environment info

No response

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[t-hamano]

This issue looks similar to #44055. I have narrowed down the problem area to some extent, but have not yet resolved it.

[mcsf]

This issue looks similar to #44055. I have narrowed down the problem area to some extent, but have not yet resolved it.

Thanks for spotting the duplicate. I'll close this one in favour of that.