iPhone user with the updated ios14 on skinny mobile.

When updating to iOS 14 it forced a carrier setting update as well which is normal but what I’ve noticed is when making a normal voice call (not FaceTime audio) with full 4G reception it switches to 3G to make the call. As soon as the call is over, it switches back to 4G.

Now I’ve tried this in 3 separate locations in Auckland and every time it switched to 3G.

My iPhone mobile settings under mobile data for voice and date is 4G.

Has anyone else noticed this? Is there something i’m missing?

Wasn’t like this under iOS 13 and I just didn’t notice?