i have this problem as well, i think this has been said but i think that it is due to the fast retriggering of samples e.g. having the same sample triggered in 1/32 time @ 130-40bpm.

i'm not sure if the problem persisits if you mix the part down. try mixing down a small section of the beats and see if the clicks are present on the mixed down version... that would be my plan of action ;)

p.s. loved the mix on littledetroit!