I followed up this issue via email with RougeRogue, here is my reply after checking his file:
Thanks. I looked into the file and... it is quite puzzling.
The internal variable know_divinity is set to 1, as if you had already read that dialogue. And the variable marking your access to the Hall, access_hallwisdom is set to 1, meaning you have access to the hall but *not* to the archbishop, it would need to be a 2 to open the archbishop grate.
That seems to be impossible. the only explanation would be that I erroneously used the same variable name somewhere else in the game, thus setting it to 1 accidentally... but I did a thorough text search in the whole project folder and only got a result on the archbishop dialogue; a dialogue you simply can't have accessed yet. So I'm at a loss to explain this... some really obscure bug in the code, maybe, but the code with variables and conditions has always been rather robust until now.
In case this can somehow help uncover the mystery, the variable has been set after you read the last (4th) XP book in the Hall, but before you explored the Forgotten Temple, so right before you did the Crown of Tol quest. I don't know... maybe you talked to the archbishop through a wall due to a glitch and then forgot about it?
I didn't get a reply, maybe you can remember anything that can shed some light on the issue? feel free to send me an EK.bak file so I can look into it.