Thanks for pointing!
I've analysed the issue and it's related to this change in v3.32:
[2025-10-21] NEW: added support for auto-completion of custom values when editing in File List. (#69448)
The edit control that usually appeared when editing in the File List is now extended by an autocomplete object (IAutoComplete) that offers auto-completion while typing. Unfortunately, it behaves differently from the Windows standards you described, despite being a Windows component.
In the next version, I plan to enable this autocomplete object only for fields that have custom values. This way, the non-standard text movement will be limited to those fields.