We have a following problem with Direct Routing SBC: call is established between mobile phone and Teams via SBC. Teams side ends the call, but this signaling (SIP BYE) never reaches mobile phone. On mobile phone call remains ongoing, and will remain until mobile phone hangs up.
In our solution SBC is implemented as VM at Microsoft Azure. Analysis so far showed that such BYE message never reaches SBC. Problem is sporadic, but can be provoked rather easily: 1 out of 10-15 test calls results with such behavior.
Please, had anyone faced the same problem with Direct routing? Any hints for the solution?
Problem tickets were opened against Microsoft Teams and against Microsoft Azure, but no results yet.