Currently when a world is updated, anyone who joins that world will load the new version even if they are joining an old instance that has been running for a while before that update. This can result in people in the same instance running different versions of the map. Depending on how much was updated by the world author this can cause quite a bit of desync between players due to the existence of objects and triggers that exist in one version and do not in the other, resulting in a poor user experience that visitors might simply attribute to the world itself.

With the introduction of Community Labs and public worlds no longer turning private upon update, the opportunity of this happening increases as users visit public maps just as they are updated and end up on a different version than those currently in the instance.

I would suggest some manner of version controlled instancing being implemented. Upon updating a world the author can check a box indicating that this new version of the world is incompatible with instances of older versions. If players want to join instances made with the older incompatible version, indicate to the user that they're joining an older versioned instance and have vrchat download the older version, assuming vrchat keeps older versions of world uploads. If older world versions are not archived then simply inform the user that they cannot join the older version of the instance that is not compatible with the new version.