Bukkit

What steps will reproduce the problem?
1. Teleport to another world using /warp
2. Teleport back to to the first world using a warp sign
3. Most/all of your inventory items are "invisible" - you have to relog/switch world to fix it

What is the expected output? What do you see instead?
I think this happens if you're teleporting fast

What version of the product are you using (if you say "latest" you will NOT be helped)?
build 45

Do you have an error log of what happened?
no

What are your world folder names (with proper capitalization)?
Maze and Lobby2.0

What is the contents of your config.yml and groups.yml?
PvPworlds:
- PvPArenaWorld
- DefaultPvPArenaWorld
- Maze
- Parkour
SkyBlock:
- skyworld
- skyworld_nether
- SkyBlockSpawn
MobArena:
- Lobby2.0
- Mobarena
- JungleMobarena
- NetherMA
- FrozenNightmareMA
- DesertMA
- MineshaftMA

useSQL: false
splitHealth: true
splitHunger: true
controlGamemode: false
separateGamemodeInventories: false
creativeGroups:
- creative
sql:
  host: localhost
  port: '3306'
  username: username
  password: password
  database: database
  prefix: multiinv_
SaveInventoryOnQuit: false
compatibilityMode: false
xpfix: false

What is the entire list of plugins on your server (doing /plugins on the console and pasting the output is a quick method to do this)?
There's no MultiverseInventories.

Same problem here.