Teams in Kiosk on Android doesn't allow menu in calls

I have configured an Android device (Samsung) in Kiosk mode to run only Teams. It seems to work well EXCEPT when in a call you cannot tap the ellipse (...) to transfer the call to another user.  It works when you first start the phone from shutdown or after a restart, but stops working after an hour or so. 

Anyone come across this? Have I set to many restrictions on the device?