Notification Delivery Issue

Going to try and make this make sense as much as possible.

so for a couple of weeks now my phone has been delaying notifications but only with my texts and calls. This isn’t when I’m on DND or any of the new focus features.

for example, as shown in the picture below I have text and call notifications. I got these notifications at 14:46 but these have come up AFTER the actual texts and calls which I missed. I then cannot access these texts and calls from the notification centre. In fact I can’t access any of my notifications from where you swipe down on your screen.

sometimes if I turn my phone off and then on again it stops doing this but only for an hour or so, usually less.

also if I answer the text before I get the notification it still gives me the notification too