I did this mod, which amongst other things adds a door to each and every guild's chapter, all was fine and dandy until I stumbled upon a weird error, while morrowind loads my mod (before the menu) I get:
If I hit "yes" and run the game everything works save for that specific door (which I did add in with my mod along with several others) which doesn't appear in game and it is missing.
I tried killing the affected cell with TESAME and redo the door but as soon as I do that the error pops back in. In the construction set everything's just fine (no errors of any kind). I am pretty lost, anyone knows how to deal with it?

Note that this happen on my main rig (which runs MSGO and a handful of mods as well) and on my secondary rig (which runs vanilla morrowind).

Edit: At first I thought I messed up something by accidentally deleting a tapestry in the guild, but after further attempts at recreating the condition of the bug by placing the door over and over, saving and launching the game after each step I discovered I get the error AS SOON AS I set the door to teleport in my mod's custom cell.

The thing that puzzles me the most is that I did the same EXACT thing for other 14 doors in all the other guilds chapter and I never experience this bug before.

Uhm, I'd try counting the number of door references against DoorMarker references in your destination custom cell, if it is not the same there may be one DoorMarker still pointing to the removed door.
I think deleting cells from out of CS details window (e.g. tesame, Enchanted Editor...) I sometimes forget updating deleting every thing involved/related, so whenever possible I try to delete (ignore) things from CS details