Ghost-block piston heads are created by immediately powering a piston after rotating it. (rotators enabled).
Using version 20w20a.

well, that's not rotating block that causes it but the piston behaviour itself. If you would fix it I would need to fix piston bedrock breaking as is stands in the game.

This is exactly what happens with bedrock breaking scenarios where one piston is replaced with another - here it is just rotated, instead of replaced.

Thanks for clarifying