Yes, if the converter has excessive pull-back (spacing from mounting pads-to-flexplate when fully engaged) then when it is bolted up, the hub will disengage from the pump rotor.
It can also damage the pump if the hub jumps up on top of the rotor!
Proper spacing is 1/8" to 3/16". Thin, flat washers (must be the same thickness) can be used to take up some excess gap.
