Unexpected Shadow cubes

[Sitrus029]

What are you trying to do, and what do you expect to happen?

unsuccesfully trying to paint/move over a cube that i interacted a second ago. Acts like a cube isnt there at all (or like its locked, but its not). I have deleted\disabled all plugins and did not lock a cube.

car_tinted.-.Blockbench.2026-09-06.15-36-22.mp4

What happens instead?

The only thing that helps is reopening the blockbench. But the issue does not disappear for long - different cube becomes a shadow cube in a new session

prev.mp4

Model format in which the issue occurs

Java Block/item

Blockbench variant

Program

Blockbench version

5.1.6

Operating System

Windows

Installed Blockbench plugins

none

Are there any console errors?

[Sitrus029]

also suspect shadow cubes only created after dup;icating existing cube

[JannisX11]

This is typically an issue that people report when two cubes overlap each other so they can't see the changes on one. But in the second video, it does look like you click through one cube.
Does the cube remain there when you delete everything from the outliner?
Also does this happen in a clean installation of Blockbench, for example in the web app (web.blockbench.net). You have a bunch of plugins installed, and some might not have implemented "disabling" correctly and might still have some effects even when disabled.