I also have had this issue since going to .180, I would suggest going to .175 to see if you're able to achieve UMA stability while retaining bluetooth use. I am currently at .180 and will roll back to .175 this evening to see if that helps with the issues.

I have a Linksys WRT-300N at home running dd-WRT using WAP2 and WMM. When I use my stereo headset on UMA, it always drops immediately or it never even makes the call to begin with. When paired to my Jabra BT800 it works fine with UMA.

I used to be able to use the headset for about 20 minutes without a problem on .175.