Minecraft Version 1.21.1
Fabric Version 0.17.2
Vanish Version 1.6.6
Immersive Portals Version 6.0.6
When Vanish and Immersive Portals are enabled together, using the /vanish command to become invisible (or to reappear) does not properly update visibility for other players within their loading range. Other players will still see (or still not see) the player until they move out of the loading range and then come back within it.