Minecraft 1.16.5
Forge 36.0.40
Create 0.3e

When a contraption goes above the 255 build limit and the cart is broken, any glue is left in world above that height limit. It is only visible if holding the glue. Any blocks that were in that contraption and would place above the build limit are then voided. See image below for example.

EDIT: I would assume the blocks being voided would be expected as they were attempting to be placed in a non-placeable area but the glue remains seems like a bug.

This is likely because superglue is an entity.

Issue should now be fixed in dev branch, thank you for the report!