White background on phone

[Cress]

Hi everybody, I followed a tutorial for a side scroller game and I tried it on two different android devices. It works but on my phone the background becomes white after like half a second of the game start, only the player sprite remains and goes on moving, while on browser and on the other device the background is fine. 

I noticed that if I set the player x velocity to 0 (thus not moving and all is still) the background has no problems.

I'm using AUTO for the graphics, is it a matter? I tried WebGL but my phone doesn't support it. The background is on a layer of its own.