Once of our clients is having a problem with the Hold soft-key. All of their incoming calls go to a blast-group, so every phone in that group sees every incoming call. The problem occurs when one of these phones has a call connected and wants to place that call on hold. If they press the hold softkey while there is an incoming call displayed the phone will automatically answer the incoming call after placing the original call on hold.
How can I keep this from happening?
For the UC500, 12.4.22.T2 versions were not supposed to be released. Those images were actually taken down because they have a lack of testing on the UC500.
The 12.4.22YB4 versions have gone through some testing and have been tested as a family with the rest of the code in the software pack.
If you are afraid of the early adopter code, then then 12.4.22T2 code is not for you either. The code bases aren't very different. Both are running CME 7.1, currently you are running CME 7.0.