T46G - Bluetooth Headset Issue

[Jethro]

We have a bunch of T46Gs and we're having problems with the bluetooth on them, we've tried lots of different firmwares, but there doesn't seem to be any difference. We're using Jabra Motions which are included in the yealink compatibility list, the bluetooth just seems to disconnect (ocassionally mid call). When we want to reconnect them sometimes we just have to go into the menu then and press connect on the headset but the majority of the time we have to remove the paired device, remove the USB bluetooth adpater and plug it back in then re-pair the devices. Why would this happen? Has anybody else had any similar issues?