[MC-298559] Box and Bundle Yeets No longer working in 1.21.5

Shulker Box and Bundle Yeets based on droppers now burn immediately, this affects dozens of builds, including the straight rail 1728, as well as multiple sorting and storage systems, I am getting multiple msgs a day about my builds not working. This update would require 2 different box yeets, one pre 1.21.5.. This causes a major headache for users. The box and bundle yeets are already pretty widely shared and used by now. Any help would be great I’ve spent 2 years developing these builds, they no longer work, and require different systems depending on version now due to the lava burning the items earlier than previously…

Environment

1.21.5, All compact dropper based shulker box and bundle item yeets are no longer functioning in 1.21.5...

Comments

[Mod] turbo 2025-06-05T13:29:32Z

Sorry, but what bug are you reporting here? All I see is a complaint that something you previously built doesn't work anymore. That's not a bug, per se. If you could provide the exact steps to reproduce the issue and describe the observed and expected behavior, as well as explain why you think this is a bug and not a change in game mechanics announced in a changelog, I'd be happy to take a second look.

This ticket will automatically reopen when you reply.

Mike Kurasz 2025-06-05T13:34:38Z

Shulker box and bundle item yeets.. they take all the items out of shoulder boxes and bundles using lava.. they work on most previous versions since the observer but they just stopped working and it affects many builds, a few that took many months to develop.. I can show you a video link of the box yeet before and after the latest change..

Mike Kurasz 2025-06-05T13:36:41Z

These are vital for terminal technology as well as programmable systems as bundles and Shulker boxes maintain item order, and this is vital for computational and storage as well.. these are instant item extractors for super fast and large systems…

[Mod] turbo 2025-06-05T15:16:56Z

Hi, and thanks for the follow-up.

I can tell this issue is important to you, especially given the time and effort you've put into your builds. I'd like to give this a proper review, but I still need a clearer understanding of the exact bug being reported.

Right now, I'm seeing descriptions of specific redstone contraptions like "box and bundle yeets" or the "straight rail 1728," which sound like community-specific build types or terminology. To make this actionable for the Mojang team, I need a minimal reproduction case that clearly shows:

The steps to reproduce the issue using a fresh, unmodified world.
What you expect to happen.
What actually happens in 1.21.5.
Why this seems to be a regression or unintended behavior, meaning how it differs from previous versions and why that difference breaks expected vanilla mechanics.

If you have a video that clearly demonstrates this difference, please feel free to share it. But ideally, also describe in plain terms what the setup is doing and how it's affected by the recent update.

This ticket will automatically reopen when you reply.