Ringing even when on silent

My phone is on silent mode and calls are still ringing through.

Silent Mode is turned on, I've double checked many times.

These are not favorite contacts that are calling, they are random numbers calling (I use my cell for work).

My phone is not put on Do Not Disturb.

This has happened before, but it usually only rings once or twice before going back to ringing through my bluetooth headset. I can still answer calls on my headset without issue, but I receive a lot of calls with work, which is why I keep my phone on silent. Is there a bug in the system that's causing this? Version iOS 14.1