[1.21.1] Flashback 0.36.0 ReplayServer crashes with Create 6.0.9 (chain_conveyor clientbound packets, even in empty worlds without blocks)

[DefomCode]

Mod Name

Flashback

Mod Homepage

https://modrinth.com/mod/flashback

Minecraft version

1.21.1

Describe the bug

Flashback 0.36.0 ReplayServer crashes with Create 6.0.9 on empty worlds (chain_conveyor clientbound packets blocked by Connector).

Steps to reproduce

1. Set up NeoForge 1.21.1 with Sinytra Connector 2.0.0-beta.12+1.21.1-full, Forgified Fabric API 0.116.7+2.2.0+1.21.1, Create 6.0.9, and Flashback 0.36.0.
2. Create a new empty world (no blocks placed, no Create items used).
3. Record a short replay (e.g., 10-30 seconds of walking).
4. Open the replay → crash within 1-5 seconds.

Tests performed:

• Without Create mod: Replay records and views perfectly (cameras, keys, export work).
• With Create mod, but no blocks placed: Game launches fine, replay records OK, but viewing crashes with the same error.
• Note: The world is completely empty — no chain conveyors or any Create blocks exist, but the crash still occurs due to global ticking.

Logs

crash log => https://mclo.gs/6OHVxVP

Additional context

Stack trace points to Create's CommonEvents.onServerTick() → ServerChainConveyorHandler.tick() → sync() → NeoForgeNetworkHelper.sendToAllClients() → broadcastAll() → NetworkRegistry.checkPacket(), which blocks the clientbound packet in ReplayServer.
Mods folder contents (ls mods): connector-2.0.0-beta.12+1.21.1-full.jar, forgified-fabric-api-0.116.7+2.2.0+1.21.1.jar, create-1.21.1-6.0.9.jar, Flashback-0.36.0-for-MC1.21.1.jar.
(Note: Crash log mentions Flywheel, but it's not in mods folder — possibly auto-added by launcher as dependency.)
No similar issues found. Workaround: Remove Create for replays, but defeats the purpose of using it with Flashback.