(First I am french so please don't blame me for my english ^^)

So, recently, i saw modded and patched, unlocked app on site like apkfiles or other mirror. I tried to send a patched app to my friend with CM Transfer (filed was groove coaster 2 with all song patch). When he launched the app, the patch didn't work, he couldn't download paid music from the game (nothing appeared). I thought that was the same type of patched apk file that i was sending to my friend. He downloaded patched games on site like that and the patchs was working well (my friend's device is not rooted). Why did the patch not work with my lucky patched apk ?