Hello,
I'm have the same problem but with checkboxes when I use several instances of a subform.
Allthough the checkboxes are set to "global" and have the same naming!
As I mark them, only the checkboxes in the first instance get marked.
The ones in the other instance of the subform are still blank.
Untill now, I didn't find the reason or an solution for this problem, cause text fields etc. are working fine.