well there's also a bug where the block just covers the player and they can't move until the block is moved back off the player and one where the player gets stuck to the side of the block just moved like it's cliff hanging, so it's hard to tell what you want help with without saying so..
i believe its just an odd reaction to the platform behavior, lerp and collisions. lerp is a nice smooth effect, have you tried using a different behaviour to move the blocks, like bullet, to see if this eliminates the effect?