Shulker boxes don't conduct redstone signals when open. However, they don't trigger redstone updates around them, causing redstone components to not react to the changed conductiveness of the shulker box.
To reproduce
In this contraption, the redstone lamps don't turn off when a shulker box is opened:
[media]In this contraption, they do:
[media]Video
[media]Linked issues
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Comments 4
since 1.20 they dont even depower at all so open shulkerboxes are still conductive. probably not intended?
Blocked by MC-263879.
I'm unable to find any difference between the behaviour in 1.15.2 and 1.16-rc1.
The redstone lamp only realizes that it's no longer powered once it receives a block update; when the shulker box opens, it doesn't give an update to other blocks around it. I believe that's your issue; I'll rewrite the ticket accordingly.
Here's a video in 1.15.2 –
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