Why does my galaxy tab 2 jump back to the home screen but only when im playing candy crush?

I can use mt galaxy tab 2 for every thing with no problems until I play on candy crush it loads up to the game but as soonas I start playing it returns to the home screen for no reason can anybody tell me why this is my second tab to I sent the 1st one back for the same reason as I thought it was a problem with the tablet but it cant be as it is happening again with this one ?????????????