Strange problem, this one... My party is at Illefarn Ruins and at level 15, but Enalee is still 12 and cannot level further. When I select "Level Up" in the Character Screen, I select her class (Druid), then I click on "Recommended" until I come to the summary of changes for this level. After clicking on "Finish", the Levelup-Screen disappears, and Enalee is still level 12. Her alignment is still Neutral/Good (50/100), so that can't be the cause. I re-leveled her by giving -85000 xp and giving them back a minute later, but still the same: Everything goes fine until leaving the summary screen, and that's it then. No level 13.
To make sure that this problem is bound to druids only, I created a test module with just 1 rural area. I entered this module with one class after the other, from Barbarian to Wizard, and cheated the level up with "givexp 120000". Every single class, be it a male or female, goes to 13 and beyond without any issue. But not the druids. They seem to be stuck at 12.
The game is a clean installation from about two weeks ago. No custom content, no override scripts, no hakpak, no modificiations to the modules themselves. Game version is 1.23, called "Neverwinter Night Collection" with NWN1 + both XPs and NWN2 + XP1 and XP2. It runs on Win XP, SP3, and - contrary to NWN1 - did not crash once since installation.
Now I'm lost

I have no idea where to look. Either I don't understand the class Druid (never played it before), or there is something wrong in the default package for Druids. Any help or even a hint would be great!
Thanks.