PMP430 SM's not joining correct AP

I need help! We are working to upgrade our gear to 450’s but we do still have many 430’s in the field. I am having an issue that I’m hoping you guys might have some ideas for. I have been talking with an engineer but wanted to post this in case anyone else had thoughts. First of all I will say I do realize its best to have seperate color codes but this network is older and havent had issues until now, out of the blue.
Last Friday night we had a customer open a ticket for poor speeds. We looked and she was on the wrong AP. We have a site with 3 430 AP’s that all have the same color code. Looking closer at this we discovered the AP she was normally on only had two customers on it. That AP should have 15 subs. On Thursday the 30th these customers moved off this AP. We did not make any changes or do any work around this time frame. Below is the steps we have taken over the last few days and our results.
Ran an AP evaluation on a few SM’s to move them back to the proper AP: This did not work. The AP evaluation does not even show the AP the customers should be on
Rebooted the AP: After doing this the AP had one customer. There is one SM that can only hit this AP and no others. The rest of the SM’s are on AP’s they shouldn’t be.
Put AP is SM mode and ran spectrum analyzer: We did see a little signal where the AP is. I don’t think it was enough to cause an SM not to sync up but keeping this in mind for further testing in steps below.
Updated firmware in AP to 13.4: All SM’s are currently on 13.4 but the AP’s are on 12.1 until next maintenance window for updates. I updated this AP to 13.4 but still can not get more than the single SM over to it.
Took spare 430 on site: We put a spare below the existing AP (20 feet lower, on the ground), turned off the existing AP and fired this one up with the same 5660 frequency. No SM’s joined it.
Used 450 to run spectrum analyzer on site: this should that the AP had equal RF output to the other AP’s on site.
Ran spectrum analyzer using customer SM: First with the AP off. 5660 was clean. Then with AP on. This should that the AP the customer should be connected to was 15 dBm stronger then the one she is on. The AP she is on is -86. Her normal signal on AP she should be on is -72 or so.
Changed frequency on AP: Although I do not see noise at the AP I thought it would be worth a try. I tried 3 other frequencies in the 5.4 range and still could only get the one SM to come onboard with that AP.
Replaced AP and antenna with spare: I still could not get any customers to join.
Tun of frequency in SM: I went into the customers SM and turned off 5680 which is the AP she is connected to at -86. After doing this she joined the correct AP with -73 and SNR -24. 
Changed SM from select AP with best throughput to select AP with best signal: I found another SM with very poor signal because it is not on the right SM. I changed this setting to see if it would help and it did not.
Any thoughts or ideas on things that may have caused this to happen? Any things to try?

Out of curiosity what were the other three frequencies that you tried on this AP?