during the seaport spirit realm quest, when one accesses the exit from seaport, the passage is only one-way. this is not a problem immediately because the player can homing compass back to seaport.
later on, if the player accidentally walks through through that passage, after using the homing compass to recall, they will be forced to redo the entire dungeon from start to finish with respawned enemies. it becomes extremely tedious extremely quickly, especially given that with the sheer amount of enemies spawning in this area you are going to have to recall back to seaport 2-3 times.
suggestion is just to add a return gate. i'm not sure if it's not there for thematic reasons or if it's a genuine oversight but it makes going through this very well designed area feel like pulling teeth!