Notification sound but no banner/notification can be found from any app...

Throughout the day I will hear the notification sound from my phone, a fairly normal sound sound that has been wired to my dopamine production over the years. Until recently 100% of the time there would be a banner with the notification and I would see it, launch the app to read and reply (normally Instagram) and then get stuck doom scrolling for an hour. For the last few weeks though I have been getting ‘phantom notifications’ — the regular notification sound will play and I’ll check my phone but there isn’t an alert/banner/notification to be found anywhere. I’ll check right through the notification centre but nothing new and then I’ll launch apps to check their notifications and again nothing. Now this doesn’t happen 100% of the time, I still get the notification sounds with real notifications as well from text messages, emails, Instagram and so on. It’s something separate to a regular, real notification and is very annoying. Happens at random times each day and doesn’t seem to link up to anything, have any consistency. It’s driving me quite mad honestly.