Wikia has an app as most of you know. And it is only available on Iphone. Though, you can get a separate app with one wikia only (Example: five nights at freddy's wiki). So, those apps are for android and ios that don't have the my wikia app but they might have it in the future.
If you find a bug with the app, go to Special:Contact/bug
The app is very popular and most contributors are on wikia. About 60% of users are on mobile using wikia (as said by wikia). So there might be some bugs that might not be reported by mobile because it isn't like deskstop because you can't type a URL fast.
I am not staff so if you have any questions please ask local wikia staff.