piston head stays after block break in creative

I created a loop with repeaters (2 ticks on, 2 ticks off);
I placed a repeater with one delay facing a block and a piston above it, facing up;
When breaking the piston (that was expanding-retracting at the mentioned rate), sometimes the piston head would still be there, floating.
I've tried it with other directions (horizontally and when facing down) and also with sticky pistons, and it still worked.
When placing blocks next to the piston head, it disappears (block update)
But, when trying to do the glitch with the repeater facing the piston directly (with no block being the power source), the piston head would sometimes glitch, but only until the next block update, coming from the repeater.