Bossbar from Lobby becomes a "Ghost Bar" when switching to a server with BetterHUD

[gummiangler]

Server version

Velocity 3.4.0, Tab Bridge on Paper 1.21.11

TAB version

TAB v5.5.0

Plugin list

Proxy:
[17:27:56 INFO]: Plugins: velocity, commandwhitelist, forcepack, luckperms, plan, proxycommandmanager, velocity-scoreboard-api, tab

Backend:
[17:19:55 INFO]: Bukkit Plugins (12):
[17:19:55 INFO]: - BetterHud, ForcePack, LuckPerms, Multiverse-Core, Multiverse-Inventories, Multiverse-NetherPortals, PlaceholderAPI, Plan, TAB-Bridge, UltimateAdvancementAPI
[17:19:55 INFO]: ViaBackwards, ViaVersion

Describe the bug

I am experiencing an issue where a Bossbar configured only for the Lobby server stays visible as a non-animated "Ghost Bar" when switching to a sub-server. This sub-server uses BetterHUD, which also utilizes Bossbar packets for UI rendering. It seems there is a conflict or a race condition between TAB's removal packet and the backend server's HUD initialization.

Expected behavior

No bossbar

Steps to reproduce

1. Setup: Install TAB on the Proxy (Velocity) and TAB Bridge on all backend servers (Lobby and Challenge).
2. Configuration: Configure a Bossbar in TAB that is restricted to the Lobby server (using display-condition).
3. Initial State: Join the Lobby server. Confirm the Bossbar is visible and animating correctly.
4. The Trigger: Switch to the server (which runs BetterHUD). BetterHUD uses Bossbar packets to render its UI elements immediately upon join.
5. Observation: The Lobby Bossbar does not disappear. It remains at the top of the screen, frozen (animations stop), overlapping or sitting alongside the BetterHUD elements.
6. Persistence: Switching back to the Lobby or to a server (without BetterHUD) does not fix it; often, a full disconnect from the Proxy is required to clear the "Ghost Bar."

Additional info

The issue does not occur when switching to a server without BetterHUD.

The Bossbar is correctly configured to only show in the Lobby (via world/server restrictions).

Even with TAB Bridge installed, the "Remove" packet seems to be ignored or overwritten by the client because the backend server (BetterHUD) immediately starts sending its own Bossbar packets.

Checklist

• I am running latest version of the plugin
• I have read the wiki to make sure it's not an issue with configuration
• I ticked all of the boxes without actually reading them
• I have read the Compatibility wiki page and am not trying to run the plugin on an unsupported server version / platform
• I am willing to cooperate to get this issue resolved faster, including providing any additional information requested or testing new builds

[NEZNAMY]

There was a Velocity bug that was compensated for by TAB. Later, the bug was fixed, but only partially. Now, not compensating for the new bug will cause disconnect and compensating will cause this. I am not sure if I can fix this myself. I suppose I can try to see if Velocity calls different events for players who get kicked than those who don't.

Issue after velocity partically fixed this bug and I removed compensation: #1593
My original issue on Velocity issue tracker: PaperMC/Velocity#1529
My new comment on the pull request that partially fixed it: PaperMC/Velocity#1656 (comment)

[gummiangler]

@NEZNAMY
Thanks!
Is there an API that can disable bossbars from TAB per player so i can make an own plugin to disable the bossbar when switching server until fixed?

[NEZNAMY]

No and it wouldn't solve the problem. The issue is that currently there is no way to know whether bossbars were cleared by Velocity or not. If not, plugin should do it to avoid duplicates. If yes, doing it again will cause disconnect.

[NEZNAMY]

After thorough testing (before and after my changes to fix the linked issue), it turns out there is at least 1 issue on TAB's side that can be fixed. I will do it tomorrow.

[gummiangler]

@NEZNAMY
I was able to solve my problem with a quick fix. I already implemented my own commands with own flow to switch between servers. I just added a line (in that velocity plugin) that executes the bossbar toggle command for the player before teleporting. It works. Now the plugin will turn off the bossbar from TAB, switching the server and eventually turning it on again.

[NEZNAMY]

Please try new build from actions without applying your workaround.