Steps to reproduce the issue

1. Create a new custom field of type 'list'. Set multiple to 'no'. Set subform only to 'yes'. Add several unique options to the list.
2. Create a new custom field of type 'subform'. Add your new list field to the subform. Make sure repeatable is set to 'yes'.
3. Create an article where you can edit the custom field.
4. Add several rows with different values set in the list.

Expected result

The custom field returns the raw value consistently, preferably as a string since it is not allowing multiples. An array with a single item would also work.

Actual result

The custom field returns the raw value inconsistently - sometimes as a string, sometimes as an array. I can work around it, but the inconsistent behavior feels like a bug.

System information (as much as possible)

Joomla 4.1.5
PHP 8

Additional comments

Happens regardless of list layout.