Bedrock client (protocol 1001 / MC 26.x) disconnects on join when a long boss bar title is sent

Describe the bug

A Bedrock client on the newest protocol (1001, MC Bedrock 26.x) is immediately disconnected (RakNet CLOSED → "Bedrock client disconnected" / geyser.network.disconnect.closed_by_remote_peer) about 1–2 seconds after joining, with no server-side error. The client itself closes the connection while parsing a packet Geyser sent.

After logging every outbound packet, the cause is a BossEventPacket with a very long, formatting-heavy title produced by the TabTPS plugin's boss bar. Geyser forwards the title verbatim; the new client rejects it and disconnects. Older Bedrock clients tolerate the same title.

This is not boss bars in general — short, plain boss bars (e.g. from an auth plugin) work fine on the same client. Only the long/format-dense one crashes.

Steps to reproduce

1. Backend (Paper) with the TabTPS plugin, boss bar enabled (modules tps,mspt,ping).
2. Connect with a Bedrock client on protocol 1001 (MC 26.x) via Geyser.
3. The boss bar CREATE packet is sent → client disconnects within ~1s.
4. A/B confirmed: TabTPS boss bar enabled → always disconnects; disabled → joins fine.

Evidence (captured outbound packet)

The offending packet, logged just before the disconnect (section signs shown as &, (len=...) is the character count of the title string):

BossEventPacket {action=CREATE, bossId=4, health=0.0100, color=3, overlay=1, title=(len=293)
'&r&7xyz.jpenilla.tabtps.common.messages/label.tps&r&f:&r &r&a2&r&a0&r&a,&r&20&r&20&r
 &r&7xyz.jpenilla.tabtps.common.messages/label.mspt&r&f:&r &r&a0&r&a,&r&a5&r&20&r
 &r&7xyz.jpenilla.tabtps.common.messages/label.ping&r&f:&r &r&a0&r&fxyz.jpenilla.tabtps.common.messages/label.milliseconds_short'}

Two notable things about this title:

• It is 293 characters, packed with per-character reset/colour codes.
• It contains unresolved Adventure translation keys (xyz.jpenilla.tabtps.common.messages/label.tps, containing a /). A subsequent UPDATE_NAME for the same boss bar has them resolved and is shorter (len=109: &r&7TPS&r&f:&r ... &r&7MSPT ... &r&7Пинг ...).

Disconnect line that follows:

... disconnected from the Java server because of Bedrock client disconnected

Expected behaviour

Geyser should sanitise / length-cap boss bar titles (and ideally other text fields) to what the Bedrock client accepts, rather than forwarding content that makes the newest client drop the connection. A title that is merely too long or oddly formatted should degrade gracefully, not disconnect the player.

Environment

• Geyser: 2.10.1-SNAPSHOT (git-master-232f873), BungeeCord/Waterfall platform.
• Bedrock client: MC 26.x, protocol 1001 (default supported protocol of this build).
• Java server: Paper, MC 1.21.x. Plugin sending the boss bar: TabTPS.

Length vs content — confirmed it is LENGTH

Reducing the TabTPS boss bar to a single module shortens the title and fixes the disconnect:

Title	Length	Result
&r&7TPS&r&f:&r &r&a2&r&a0&r&a,&r&20&r&20 (1 module)	40	joins fine, boss bar updates normally
the CREATE title above (3 modules, unresolved keys)	293	disconnects on join

So the trigger is the title length / number of formatting runs, not specific characters, and not update frequency (the short boss bar spams UPDATE_PERCENTAGE/UPDATE_NAME every tick without issue). The breaking threshold is somewhere between 40 and 293 characters on protocol 1001.

Additional notes

• Suggested fix: cap/sanitise the boss bar title length in BossBar before sending, so an over-long title is truncated instead of disconnecting the client.
• Likely also worth reporting to TabTPS that it emits unresolved Adventure translation keys (xyz.jpenilla.tabtps.common.messages/label.tps) in the first CREATE packet, which inflates the title.