Natula et al won't appear in Planar Sphere

[thankyouverymuch]

In the Mage Stronghold quests once my character's summoned to Planar Sphere and after I've spoken to Teos, it looks like several enemies are teleporting in but none actually appear.

 

What can I do except leave the Mage Stronghold quests at that?

 

I've tried resting, exiting and entering as well as reloading from an older save, but I still get the same result, whether my characters are invisible or visible. (There was a invisibility-related bug with Kangaxx.)

 

I've got BG2 ToB and the Tweak Pack from about a month ago installed, nothing else. I applied most patches except not all of the convenience ones.

 

Thanks!

[CamDawg]

The only thing that might affect this in Tweaks would be Multiple Strongholds, but I don't think it would. I do know the original, patched game had a bug where this pack of assassins could occasionally fail to spawn--Baldurdash found it originally and we fix it in the BG2 Fixpack.