I had a similar problem because of my middle name/initial in my accounts.

It was
First Middle Last on UA
First M. Last on CO

Since it is First Middle Last on my DL, passport, SS#, I called CO and asked how I can have my middle name spelled out instead of just an initial. The lady tried and had some difficulties. Then she told me she would make my first name First Middle in two words and delete the initial M. in the middle name box. Somehow it solved the problem. I'm still not quite sure if that's what she did, or how she could add another word(name) to my first name, but my accounts are since registered and linked, and I've transferred miles from one to the other and my status is matched in both accounts.

P.S. How 9-11 has made the simplest things a hassle and the way we do things.