MC-114304 no longer happens. This was useful for aligning entities, especially those inside of blocks. I fully understand if this is considered WAI as a result of the fix to MC-93631, just wanted to report it in case there's a chance.
relates to
MC-93631Pistons pop off blocks attached to their back when retracting
Resolved
MC-114304Retracting piston pushes entities standing behind the back of it