Aastra 2.4.x Reboot Issue w/ v7

So, after spending time analyzing the SIP interactions it appears that the Aastra's reboot when they receive a "200 OK" message back from 3CX after registration/re-registration. Occasionally, 3CX is sending back a "200 OK" without a contact field in it. The aastra seems to not handle this well and cause a reboot after crashing the SIP engine on the phone.

I suspect this occuring with all phones but only getting noticed on the aastra 5xi family because of poor error handling by aastra.

Best,

Mike