Action bar text persists across unrelated worlds via onScreenDisplay (scripting)

Partner Rank: Medium

Verification Builds: 1.21.23 (Build 27459537)

Regression Builds: Unknown

Summary: Action Bar text set via onScreenDisplay persists and reappears across multiple unrelated worlds.

Affects currently Live Content: Probably?

Impact: Action Bar text is incorrectly shown on world startup, even in unrelated worlds without the relevant behavior packs, causing confusion, and giving players irrelevant action bar text/titles.

Repro Steps:

1. Use scripting to call player.onScreenDisplay.setActionBar("foobar") during an event trigger, like breaking a block. (An example pack is attached here for convenience.)
2. Exit the world, then re-enter it.
3. Observe that the Action Bar text reappears without triggering the block-break event.
4. Exit the world and create or load a new vanilla world without behavior packs.
5. Observe that the Action Bar text from the prior world persists in the new world.

Observed Results: Action Bar text persists across worlds, even when not triggered again. It shows up in completely unrelated worlds.

Expected Results: The Action Bar should behave like the /title command, only appearing when set in the active session and not persisting across worlds.

Screenshots/Videos attached:

• Video showing issue (captions + audio)
• Example Pack (.mcpack)

Notes:

N/A