Come to my attention that the behavior of dropdowns changed a bit based on its contents. Not sure when this happened, as my user was not sure when the error started.
I had a dropdown which its items (timeslots) were defined in an array like ["","07:30","08:00","08:30","09:00"]
The dropdown looked like this
After the user reported the bug, I checked and indeed the dropdown had changed to this (again, 100% sure nobody touched this app last couple of months)
Seems that the first item of the array, being empty/null, causes the weird behavior. Solution is either move the empty/null to the end of the array, ["07:30","08:00","08:30","09:00",""] or use a blank instead of an empty/null [" ","07:30","08:00","08:30","09:00"]. In either case User will need to select the last item when they need to blank the dropdown, or the app needs adjustment to deal with a blank instead of the empty (samples below).
No big deal, just another annoyance.