[MC-161248] Droppers on specific locations get stuck in triggered:true

While performing some tests before upgrading our server to 1.14 we encountered a problem with droppers.

What has happened?

In the Pictures you can see a simple dropper elevator. The dropper on fourth position from the bottom gets stuck in "triggered:true" state if the elevator is used. After that the dropper remains in that state, regardless of the surrounding redstone signals.

So this behavior is blocking the function of the item elevator.

This does not effect all droppers, but a few random ones... it does not help to replace them as they stay affected when triggered once. We discovered a few more of them in our contraptions just in case you need more examples.

What should happen?

The item elevator should transport the items from the bottom to the top.

This was working in Minecraft 1.12.2, and some quick tests in 1.13.2 were successful, too.

Bypass the issue?

We discovered that this could be bypassed when the slab next to the affected dropper is replaced by a solid block (and adding another way for the signal).

So this issue may be connected to dropper, coordinates and slabs, but we haven't investigated furthermore...

Related issues

duplicates

MC-108 Droppers, Dispensers and Pistons activate when blocks are providing power diagonally or two blocks above

Attachments

dropper-elevator.zip

Comments

migrated 2019-09-17T20:50:29Z

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migrated 2019-09-17T20:50:35Z

Please do not mark unreleased versions as affected.
You don't have access to them yet.

migrated 2019-09-17T20:50:35Z

Please do not mark unreleased versions as affected.
You don't have access to them yet.

migrated 2019-09-17T20:50:35Z

Please do not mark unreleased versions as affected.
You don't have access to them yet.

migrated 2019-09-17T20:54:43Z

I did a quick test in current snapshot. It is affected as well..

RedCMD 2019-10-25T18:59:28Z

~~This has nothing to do with MC-108~~
The locational part of this bug is caused by MC-11193
The dropper being powered by the dust above is cause by MC-108
~~It seems to be a bug when dust depowering, it doesn't give a block update to the dropper~~
OR
~~The dropper isn't doing anything with the block update maybe when it hasn't fininshed its tile tick first~~
Fixing MC-108 or MC-11193 would fix this issue
I would say this report is a duplicate of MC-11193

NeunEinser 2019-10-25T21:33:12Z

Pretty sure it's just a combination of both mentioned bugs (MC-108 and MC-11193).

consider following setup:

[media]

Now, because of locationality, the dust directly above the dropper updates while either the one to the top left or top right is still powered.

When the redstone dust that QC-powers the dispenser updates, the dispenser doesn't get updated.

In fact, in the same setup when replacing the dispenser that doesn't update with a piston, the same thing happens.
You can't just replace everything with pistons, because pistons cause block updates when extending/retracting

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