sticky piston becomes unsticky when the bottom is touching the void

bandicam 2022-08-05 17-28-58-701_Trim.mp4i was building a piston door but when i activated the Sticky piston it spat out the block and became a normal piston  this only happened when i put the Sticky pistons bottom touching the void other times its perfectly normal heres a short video showing the problem  bandicam 2022-08-05 17-28-58-701_Trim.mp4