If you look at this , there is a bug in Lollipop 5.0.1 which incorrectly calculates the duration of call from the time of Call Arrival or Call Start, not when you actually start talking.
The version 5.1 came in, has anyone who has it installed can verify the bug has been corrected or not?
This issue has been corrected, just had my 5.1 update and our apps work properly again.