APKs not deleted completely - Residues left and crashes even with older version

[Alter103]

My S7 Edge has custom rom TWRP flashed. Previously realized one app got crashing after update. Can't open it. I tried to delete data, uninstall, reinstall. Still crashes. I thought it's app related bug and gave up.

Today another app got into same issue after forced update. I tried to install older APK version, but it has same issue now - can't open even older version.
What I discovered is that fresh installed app has Unread Notification count on the icon. It shouldn't be there. Even though I deleted and installed several times the notification count prior deletion is still there. Which means something is not deleted from the system completely. Tried to look for leftovers through Es file Explorer, couldn't see any visible folders. What could be done?

 

[Alter103]

Anybody has an idea?

 

[fuzzylumpkin]

What app is it?

Not many rooters or ROMers around here anymore, you may have better luck on XDA. Then again, with a device that old you may have trouble there too.

 

[Alter103]

What app is it?

Not many rooters or ROMers around here anymore, you may have better luck on XDA. Then again, with a device that old you may have trouble there too.

The first issue started with WizzAir app, and now on another local app.

Okay I will try XDA too. Yes, device is old a bit, just I didn't think it's very specific to S7, but to android system.

Thank you.