As discussed previously the porters in the frontier seem to bug out when the character using them has sideway movement.
The previous reproduced instance with the Alb relic village was annoying but not very impactful, but the solo porter is.
Depending on the arrival location at the destination the results vary, but they are consistent in that my character is dropped off with sideways velocity and significantly outside of the "solo keep".
The drop-off location varies massively, from "just outside the solo keep" to in another zone entirely. I arrived on EV instead of my target destination in some cases.
During testing this I discovered that some NPC windows and interactions seem to have a limitation to the forward momentum of the player so that Dialogue boxes close when the player exceeds a certain forward velocity. The same limitations seem to not exist for sideway velocity (strafing) and walking backwards.
The small man porter has similar issues, dropping me off outside of the normal arrival locations (depending on in which direction I am strafing at the time).