QUESTION: Pixel phone problems with incoming calls?

Hello community, I wanted to check whether there are others facing problem with incoming calls under /e/OS.

I am running a Pixel 6a (with latest e-1.21-T-dev). I realised that in most cases calls are not coming through anymore - unless the VoLTE feature is enabled.

Does anyone face similar problems?

Regain your privacy! Adopt /e/OS the deGoogled mobile OS and online servicesphone

I wonder as well if this could be related to problems that stock Android users on other Pixel phones express. Or is this from a technical point of view unlikely?