I don't know about 'bugs', as I haven't played and poked around enough. For now I am more likely to think that the BW version is purposely made more difficult and perhaps that encounter is 'too over-powering'.
The only beef I have with BW version 2.3 is it's computer resource hungry attitude. My system barely runs it, lags & sputters every now and then, version 2.2 runs without any problems.
This is what I have learned about the differences in maps/games.
Microsoft Games DS2 Version 2.2
'Dungeon Siege 2/DungeonSiege2.exe'
World.ds2map 'vanilla map' 217MB
2K Games DS2 version 2.3
Dungeon Siege 2 Broken World/DungeonSiege2.exe'
xDS2World.ds2map 'BW altered version of original map' 4MB
xDS2World.ds2map 'new BW map' 69MB
Nothing in the 2K Games install changes the Microsoft Games files. I suspect that some data is being being pulled by 2K Games from the MS Games resources, reasoning being its classed as an expansion. Note that there are two ds2maps under the BW install. I am under the impression that the smaller file is calling the MS Games World.ds2map and 'tuning' the encounter makeup which is making the BW version more difficult.
I am not sure that the DS2 Tool Kit editor v1.1 is able to load the BW files, as I havn't tried.
PS: My point, with the BW version of the original map, is familiarity but with a new twist making it worthwhile to replay. In my newbish state, its worth playing both. 
[This message has been edited by shaun1 (edited 01-14-2007 @ 05:45 AM).]