We recently configured IPMA using proxy line functionality on CUCM 5.1, the Assistants are using 7961 IP Phones & Directors using 7941 IP Phones. Incoming & Outgoing call routing works OK, but when the Assistants place the receiver back on hook or press End Call they experience a problem. In both cases the phones only displays "Requesting" and its not possible to do anything until this has finished and the normal screen is displayed - the message is displayed for beween 5 to 15 seconds so is very inconvenient for the Assistant and the Manager concerned.
I have run sniffer traces from one of the Assistants phones back into CUCM Pub & Sub and at certain times you see an Unknown error message when the requesting status page come up on the IP Phone.
Has anyone seen this before?