ToME: the Tales of Maj'Eyal

I have run into the issue of escort portals disappearing if I save during escort and reload later. The escort knows where the portal is, and runs back and forth in a 2 or 3 square area shouting "I'm making a run for the portal". They never disappear though and I never get a escort reward. Further reloading does not fix this and I have not managed to find a way to get the portal to appear. This occurred in Troll-mire this time, and has occurred in Scintillating Caves once before.

I do use some addons, however I don't receive any error messages pertaining to the portals disappearing. I use succor (I ran into this issue once before ever using the succor addon), and I use escorts enhanced, though I don't think that affects portals whatsoever.

As I said, I don't see any error messages in the log, though I will attach it.

EDIT: When escort is standing on where the portal likely is, they say, "the portal is close, to the ???."

already noted is that any terrain changing effect can permanently destroy the portal.
i have however never heard of reloading to do it...
have you actually seen the portal disappear? as in, was it in your field of vision?

No, I've never seem it actually disappear while in view, just that it is not there but the escort believes it is. Happened again today in scintillating caves. Guess I'll have to stop playing TOME on my breaks xD.

EDIT: Happened again in old forest, though I think it might indeed be from terrain changing. Escort says, I am not sure where the portal is.

Couldn't the portal be flagged as non-diggable to fix that? This is my third attempt at getting the madness version of saving all escorts, but I keep running into this bug.