Bookings: URL not valid

Hello!  We've recently had a few occasions where someone tries to join their Bookings appointment from their Teams calendar and it says the url is not valid.  It seems to work fine from outlook calendar.  It's not happening with every appointment and I can't see the issue.  One thing I did notice is that the problem occurrences had a slightly different url in the Teams calendar starting with https://visit.teams.microsoft.com/webrtc-svc/api/route?  etc

Any suggestions gratefully received!