also I can't see the problem with FILT because it completely breaks before that for me.
the large box of BREL breaks because it's retracting before the PSTN on the right can push it I think. Also, pistons can only push / pull so much, I think 32 pixels is about the default. You can set the .tmp variable to change this to a higher number if you want. Also, if it helps, the next version will have FRME .tmp 1 be non sticky.