I have worked around this by creating another column of the same type as the broken one and leaving that as hidden, this hidden column requires to the be the default and i have renamed my based as LOV column to "column2" and display this, and all is working now.
You're busy so I'm sure you are now working on the next problem. When I have some time, I may try to duplicate this problem. Perhaps it's the "does not save state" which causes the problem. I'll report back then with any new info.
I have an example here on apex.oracle.com (APEX 4.2):
demo / demo
Application 49924, page 1
The JOB column is DISPLAY as Text (based on LOV, does not save state). I can update all the other columns -- not the JOB, of course.