groove~ problem

Hy,
I have a problem with groove
I record into a buffer and many groove~ at the same time reads a few seconds of buffer~ (set start and loop start)
Now if I active the groove at the second 0 the sound that comes out of groove~ will a sound with a digital error (you hear a sort of distortion)
but if the groove I will active at the start of the loop will pass before it activates the same set seconds in the start of the loop!!
how can I solve this problem?
I hope I've explained it well if anything ask me to better understand

here the max patch