Hi all,
Bluez has a major bug in it that causes devices to drop connection intermittently. This has been reported in our forums as well as multiple times in the arch forums. The good news is that there is a fix that has been merged to Bluez mainline 2 days ago. See my post in the relevant thread: Bluetooth Mouse randomly disconnects - #24 by mynewlaptop
Is it possible to update Bluez? This will fix a very annoying bug impacting a large number of people.