Green slime momentarily disappearing while sticky piston moves

when a sticky pistons extends, it has a graphical glitch, with the green splodge momentarily disappearing

i expected there to be a sticky splodge on the piston.

what actually happened was, there being no green splodge on the piston

step 1) make a hopper clock with a stack of sticky pistons inside it, with the set up shown in the picture provided