@Squigley,
We recently upgraded our phones from 5.2.2.0501 to 5.5.1.11840 and have random phones being affected by exactly what you are experiencing.
We as well are not able to pin point it, except that its specific locations, but those locations do not have the same network topology nor the same routers or internet providers (Thinking maybe it’s a messed up packet)
Did you have any success?
