The REL has only 0 or 180 for phase.Looks to me like REL volume is way too high. Also roll off is a little too low. Try to set to 80 with REL 1/2 as loud. Also, can the REL polarity be something in-between 0 and 180? Try 160 and 200 and see if the fills in the cancellation at 60.
I will try to set the crossover a little higher and see what happens.