Initially MS released a KB about this patch causing video to stop working when recording meetings.
But it seems this patch also introduced another problem – i have now seen this at a handfull of customer sites – so not all are impacted.
Issue that occurs is that Missed Call Notifications simply stop working, everything is green, so EWS and MAPI status are ok – and it makes no difference if user is enabled for UM.
So far a tested solution is to remove this patch – but being a security patch – this is not really a perfect solution, bug has been submitted to Microsoft.
Issue seems to only occur when both of the following patches are installed
And resolution/ workaround is as follows – this has been tested at 3 different sites, with same effects