How do I Detect a Retracting Piston for an Item Display Block?

I’ve been making some full 16x16 item display models to “add” new blocks to the game. I’ve been able to get them to render correctly with a solid block underneath, drop when mined, and even interact with pistons when pushed. I can’t get them to work when getting pulled by pistons, however. I have a function that triggers when the display no longer detects its respective block:
$execute unless block ~ ~ ~ $(id) run function example:displays/move/check_4_piston
Then, it branches out into 1 of 6 functions for each of the possible directions a piston could be pushing it. If no piston is found after consecutively executing 12 spaces away from the entity itself, it supposed to go back and execute a different function in the opposite direction to check for a sticky piston or some slime/honey blocks.
The problem I keep having is that I am finding no reliable way of initiating the function when the sticky piston retracts, since all the display entity seems to be picking up is air. No such trouble for a pushing piston.