If you move from the poor-person part of elanthia to FWI manually, go2 doesn't know what city your trinket maps back to so it can't correctly create a path back to anywhere on the mainland.
When you use go2 to go to fwi, it sets a variable that using your trinket again connects to room XXXX, so it can. That variable is then unset on the return trip.
It's a shortcoming of the logic around the rooms that map from poorland <-> FWI. if you just never use the trinket manually, it shouldn't happen.
Mithrilschlong, 2015-03-10 to slightly later on 2015-03-10. You will not be forgotten!
usable Meteor Swarm, late 2020-12-30 to early 2020-12-31. You will also not be forgotten!