GY-80 wired trouble

Hello guys,

I have a really wired problem with my gy-80 module. I read the Euler angles and everything seems okay, suddenly it goes crazy. For instance I attached theta angle that is the result of fusion of gyroscope and accelerometer. As you can see, everything is normal at the beginning but it goes crazy in a glimpse. Checking out the outputs of the accelerometer and gyroscope separately I figured out that the problem is with the gyroscope.

Thanks in advance.