Our office recently switched over to the Teams Phones. I went with no physical phone and just use the Teams app on the desktop with a wireless headset.
I haven't had the particular issue you mentioned, but a somewhat similar issue with the "consult then transfer" option. I field quite a few phone calls and prefer to "consult" with team members before transferring them a call. However, with the "consult then transfer" option, if the team member does not pick up, the "Transfer" button remains grayed out and not available to click. Instead of clicking "Transfer" and letting the caller leave a VM on the team member's line, it wants me to leave a VM, so I have to end the call and resume the original call.
The normal "Transfer" option works fine, but that's not how I want to do business. I don't know if this is an issue others have seen, if there's a remedy to it, or we're just at the mercy of Microsoft until they fix it.
