Huh. I tried that last night to no avail. But I'll try it again later on a fresh save (where I haven't entered Naradoth yet) and report back.
Edit: All right, did some tests. I think I've solved this bad boy. (Tldr version in the last paragraph.)
Test 1 - German, fresh save (a save where I've never been inside Naradoth): it worked!
Test 2 - German, old save (the save I uploaded where I'm standing right next to the button): it didn't work.
Test 3 - English, fresh save: surprisingly, it worked! (This was surprising because I had tried a fresh save earlier when I tested adding a parent reference to the door. At first I thought that this had messed it up somehow, or that maybe I repeated whatever I did the first time that kept it from working.)
Test 4 - English, old save: no surprise here, it still didn't work.
This, along with Aro's post, gave me an idea. I thought that maybe Aro, likely being less obsessive than me (

), might have moved on and explored elsewhere before returning to Naradoth. So - Test 5 - I loaded the old save (in English), teleported to the Mountain Monastery, returned to Naradoth, went through the dungeon, hit the switch, and... lo and behold, it worked! I thought that there must have been some information about the area that was retained in the memory when I saved, preventing any attempts to make the switch work from, uh, working. (Close, but no cigar.)
This also suggested to me that there's some element - an action on the player's part, what's currently loaded into the game's memory, etc. - that prevents the gate from working sometimes but not always, as I was using the same data files when I first encountered the problem as I was when it was resolved. I wasn't sure what that element might be, though. One thing I did know is that in all attempts where it worked I zipped right through Naradoth, area1 -> area2 -> switch and ignored the enemies and so on. Whereas on the old save, I had taken a great deal of time in the second area, gone back in the dungeon for a moment before hitting the switch, maybe alt-tabbed out to play some music in the background, maybe even exited the game and come back to it later. So it might be something like if the first area is no longer stored in the game's memory, the gate fails to work. (On the earlier failed attempt from a fresh save, I just TCLed up to the switch, ignoring the Naradoth areas entirely until afterward.) This led to...
Test 6 - I loaded the old save in English, teleported to the Mountain Monastery, and came back. But instead of going through the dungeon, I TCLed straight up to the switch again. And guess what: the gate didn't work this time!
So based on these tests, my conclusion is that if you don't have the first area of Naradoth loaded into the game's memory, the gate doesn't work; if you do, it does. Of course, you'd need more tests to confirm this, but I think I've got a pretty solid basis for this theory at this point. Plus, it makes sense intuitively. Plus, I don't feel like doing any more testing today.
