Going busy as soon as a call is received?

When you receive a call your status is set to in a call for the duration, all fine. But one of my colleagues is having a weird issue where Teams seems to automatically switch them to busy for 10 minutes (exactly, we timed!) every time they receive a call whether they answer or not. I know the status function is questionable, but it seems so specific with the exact trigger and length.

We cannot figure it out, and while it is at most a minor inconvenience it has got to the point where we need to know. Why? Why would it do that?