Do you use iCloud drive?

This might be a stretch as I am taking a guess at the implementation, but apps can sync with iCloud Drive and I keep getting app folders showing up after telling it not sync but the prefs reset after certain states(not quite sure when/how)-- it then creates a new sync folder when interacting with the app again. (after having turned off sync and deleting the folder -- once it resets)

I am wondering if that app had that feature (icloud drive syncing) and something of the reverse is happening. Where you have a document still on icloud drive from when you installed the app. Maybe there is some action or state change going on after interacting with drive on a mac or something similar. And now it's created the right circumstances for icloud drive to try and sync the file but there is no app on any device so it downloads the app instead since it's missing and there is some dangling file looking for its home.

It still doesn't make sense why the app started silently downloading itself 3 days ago when I haven't had it installed in over a year. I do use iCloud drive but do not see anything related to the app inside of it.

Did you update iOS before it started happening? Wondering if they may have introduced a regression that is now trying to re-sync everything after the last update (sync files may be hidden, I set files to always show)

I updated after noticing the issue