If you change the column a table is sorted by on for example admin/content from updated to content type by pressing the return button, then the focus order is reset. The next tab brings up the "Skip to main content" link, you are back at the top of the DOM (SC3.2.1 & SC2.4.3 - check table_header_focus_drop.mp4).
Discussed and iterated on the issue with @mgifford, @the_g_bomb, @katannshaw, and @drupa11y
admin/content and change the column the table is sorted by by keyboard.Active
4.0
User interface
It affects the ability of people with disabilities or special needs (such as blindness or color-blindness) to use Drupal.
This would be really annoying as a keyboard only user.
Yes, this is an issue in Core though, not just Gin. With Claro (and Olivero) and /admin/content/media I have the same effect.
I think this is a general issue with tables in forms. Maybe Tables are elsewhere though.