If you attach a sign to a partial block, the sign is placed on the side facing you or on top, even if there is a solid block. This bug can be used to break bedrock.
How to Reproduce
Place a lower half slab, with a solid block directly above.
Place a sign on top of the slab.
Expected Result
The sign should not get placed.
Actual Result
The sign does get placed, deleting the solid block.
Related issues
Comments

Thank you for your report!
We're actually already tracking this issue at MCPE-102371, so I will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
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