Hi Damien2003gt,
I don't know exactly what your problem is, but if it is linked to synchronization, you should be aware there is a bug in Logic X, concerning synchronization and if you make a loop in Logic.
Have a look at the attached picture.
Options containing "SPP at Cycle Jump" are buggy on first loop, creating a drift in synchronization. You should use first or last option.
Regards,
Y.