Yes same behaviour here, I'm on Three IE (Roaming atm). I've been using LTE only for months since installed Graphene, but only realised couldn't do calls through the network recently. I only get calls through communication apps.
While I was using the phone with LTE only I was able to receive SMS and use Data without any issue. I will try to change to 5G/Enable Volte and check if I can do cell calls.