This may have to do with configurations or FW/SW bugs. Please make sure you are on latest Medpro/DS1/IPSI FWs and CM latest patch. Please also refer to the following KB articles for various configurations you need to verify. If you cannot view the KBs please reply to this thread and let us know.
https://kb.avaya.com/kb/index?page=c...=1368593663154
https://kb.avaya.com/kb/index?page=c...=1368593663154
https://kb.avaya.com/kb/index?page=c...=1368593663154
https://kb.avaya.com/kb/index?page=c...=1368593663154