There are 2 issues caused by the lack of support for housing islands in the model. The main issue only occurs with guild housings as far as I'm aware.

1. Incorrect world name. A minor issue that causes your current world name to be displayed as the name of the housing island. This affects things like Discord rich presence, bomb bell command and possibly more. Fixed in #2477
2. World state not being updated to WORLD when switching worlds via travelling to guild housing. This is the main issue, if the custom loading screen is enabled it will never leave the "Receiving terrain" stage and upon pressing esc you will be unable to do almost anything except move. Certain overlays do not work, you cannot chat or leave the island via the usual menu. The only option is to leave the server. If the loading screen is disabled you are able to leave and rejoin the housing the usual way, but certain overlays are still missing until doing so. Fixed in #2826

How to reproduce

Issue 1. Join any housing island.
Issue 2. Have a player be on a guild housing island in a seperate world to you and join via the public housing list. Have not tested joining via invite.

Demo of joining island with loading screen disabled, followed by enabled