Weird lag issue

This weird thing happens every now and then. I start a race and the game lags way too much, almost to the point where I barely can keep the car in the track. In the main screen, if I spin the car the animation is not smooth. The workaround I found is to press the menu button on my phone to put the app in the background and then open the app again, the issue is immediately solved. This makes me lose any ongoing Duel I'm playing, except for races in Career mode, which can be resumed. My phone is an Android with more than enough RAM and processor. Any idea what could be the reason? Have you experienced the same?