Thanks Collin i was facing today with this issue, and your post saved me from lot of troubleshooting!
It was a weird case because well at first they told me that they had issue with ip phones with that model, i had an extended ping to the ip phone, and i notice that everytime the user call on an capable N AP in this case was a 93 AP the ping was unreachable to that phone and then it came back and had lot of packet lost...
We try then doing it on a ap 61 as they are replacing old aps 61 for 93, and well eveyrhting was good... so it sounds to me it was some kind of uncapibility.... i did a fast search ont he forum to see if there was something about this phone and voala your post hehe, also applied the change you mention on the template that is on the VRD... and now its working...
Anyways thanks man!