After exactly 8 seconds of not moving the controllers they are reported to steamvr as though they had gone to sleep or disconnected. This happens regardless of whether or not a capacitive sensor is active (holding the controllers in my hands), though fully holding down a trigger/button can prevent it. It is incredibly infuriating especially in casual experiences like vrchat where you don't move your hands around a lot, but can also impact other games if you hold your hands too still.
At first I though this was a bug in Meta's firmware because the symptoms seemed to coincide with that. Then I suspected VRChat (the main game I play) because other people on the VRChat feedback forums had started a thread about a similar issue. However after testing with Steam Link and ALVR I have determined that this only happens when connected via VD.
Using Quest Pro with Quest Pro Controllers.