It's obvious that there is a bug in the code, I get the interstitial at random times, not only when I open the app. Wifi drops and then comes back? Interstitial right on top of whatever I was reading...

PS, am I the only person that puts a "cancel free trial for XYZ" in my calendar the minute I sign up for anything?

So much so, I have an "Add expiration reminder" iOS shortcut. Pretty sure I downloaded it from the Shortcuts gallery or something, it doesn't look like something I'd write.