Some pistons activate when they are placed diagonally near the redstone block

What's the bug here?

I think the pistons' behaviour is not the same how it should be with redstone themed blocks

Thank you for your report!
We're tracking this issue in MC-108, so this ticket is being resolved and linked as a duplicate.

That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.

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This is a feature of Minecraft: Java Edition redstone known as quasi-connectivity or qc for short. Pistons and dispensers can be powered diagonally if they are updated.

But why at least don't diagonal top pistons activate? Such a strange featured bug