Low FPS when launching the built apk first time

Hello, I've been annoyed by this issue over the last few weeks : my game runs very bad when I install and play the APK on my Android device for the first time. When I relaunch the game (close it and open again) it runs at 60 fps without any problems. I tried to reinstall the game multiple times and test it on multiple devices but my results are still the same in all situations, the first time I launch the installed game it runs very bad. Anyone that has an idea of what causes this issue? Thanks!