VVX 600 dial pad shortcuts intermittently working

[bdx]

I use the dial pad shortcuts often of holding 0,1,3 to reboot phone or 1,5,9 to upload logs to my provisioning server.

Problem is, they only sometimes work. They seem to work more often directly after a config reload or a restart, and less frequently the longer the phone has been on for.

Any ideas as to what might cause this?

Running SIP load 5.0.2

[bdx]

Further testing has revealed this is also happening on a VVX 400 with a SIP load in the v4 series