The calculated machine is not synced when the source value is defined and the machine name is empty.

I created an MR. I don't do any core development, so forgive me if I do something wrong.

The fix could be as simple as looking at the initial machine name and not the calculated machine name.

In 10.1.x, the code worked because the machine was being calculated via transliterate Ajax request which would set the target value after the event handler was initialized.

https://git.drupalcode.org/project/drupal/-/blob/10.2.x/core/misc/machin...
https://git.drupalcode.org/project/drupal/-/blob/10.1.x/core/misc/machin...

I hope this helps.

Thanks @jrockowitz! The only thing is that we need the MR to be created against 11.x, since issues are committed there first and then backported. Trying to switch the target branch can get really messy, so sometimes it's best to close the previous MR and re-create it against 11.x with a cherry-pick or whatever.

This also seems like a bug that should get some FunctionalJS test coverage, if it's a JS bug.

Thanks!