@gingerbeardman I have a new beta of the app out with a possible fix for this issue. Here’s the link to it: https://testflight.apple.com/join/wV1h4svp
This is a very old bug, three years is a long time, thank you for sticking with it and for still using the app. I am very very sorry to have taken so very long to find a fix. The fix is not very complicated, we were resetting the seen notification id but we were only doing so for sites where push notifications aren’t enabled (i.e. sites not hosted by Discourse). I don’t have a good excuse, I just didn’t pay close attention to the right bit of code when I first looked into this.
Anyhow, I very much hope this is fixed in the beta. As usual, let me know if that’s not the case.