Framerate drops JUST in the first run of my game.

Hello! My game has a singular behavior: Just after the first build, the frame rate drops (each time in the same frames) with drastic spikes (2 fps).

But the singular thing is that after I close the app, and I restart it on my phone, it runs PERFECTLY! (60/62/64 fps).

This happens also in the first install from Google Play. I use timelines and cutscenes at the very start of each scene.

Should I 'prewarm' something (maybe shaders/ timelines or others)?

Thanks for your help!

Valerio