It's a little late now. You needed to do some troubleshooting like reading the MIVR logs with debugging turned on while the problem was happening.

If it happens again, I would recommend:

A) Doing a reactive script debug to see if you can walk through and reproduce the behavior. Perhaps a condition changed that you did not expect and the script did what it was supposed to in that scenario.

B) Turn on debugging as soon as you hear that it is happening (System > Trace Configuration), get a couple call examples, and then make a copy of the current MIVR log file. Do not leave debugging on as it can impact the server performance!

With some log files showing an exception we can try and troubleshoot further; or, you can open a TAC case.