In very much the same theme as https://www.byond.com/forum/post/2784074
Anything that can be done to make side_map's "bugs" (effectively a dev doing something wrong or nonsensical) as clear as possible is good.

When layering a grid of objects on a plane, presorting them by layer would make any visual inconsistencies much less frantic. I've had issues where standing to the left of a stack of objects and doing something made it flicker, whereas standing on the right didn't.

Being honest, this is deranged, and I have a feeling presorting the objects would go a long way towards fixing it.