Blocks display incorrectly

This has likely come up before but I could not find a search result for it:

I have a block made up of layers B and C. The block is then placed on parent layer A.

When it was correctly displaying, turning off layer B or C turned off the block geometry on those layers. Turning off parent layer A turned off the entire block. All OK.

However, the file recently went strange without even messing with the blocks. In shaded mode, if layer B or C is turned off, the shaded geometry turns off, but the wireframe stays on without being able to grab it.

Refresh shade did not work because I could not select blocks. ClearAllMeshes did not work either.

What happened?

Matt (107.2 KB) (551.1 KB)

FYI, I was able to reproduce it, but no idea.

I have noticed that:
1 block instance added to selection.
Command: _NoEcho
Block Editing part "Marvin_wdw_5656"
5 polysurfaces added to selection.
Command: '_SelAll
5 polysurfaces added to selection. <<< 5 objects

Command: _Show
Showing one hidden object.
Command: '_SelAll
No objects added to selection. <<< still 5 objects

Command: _Hide
Command: _Show
Showing 6 hidden objects. <<< now 6 objects !

In Technical view, all objects lines are drawn as hidden !

Hi Matt- I see it, thanks. I do not have a good idea yet…

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