Anyone else seeing a weird phone bug?

Ok all, Got what I think is a bug and I have no idea how long it may have been around. Basically, if my phone is unlocked i.e on my home screen and I get a call there is no way of knowing who has called me. Swiping just goes through the home screen icons. So no answer button etc. As it is rare to get a call when the phone is not locked this could have been around for years. When locked it acts normally. So, if anyone else has seen this have they found a way of finding out who is calling etc.