Or just sloppy/lazy coding, the mod author probably should have added a script to that area that made it disintegrate when you leave the screen. But hey, no one's perfect - least of all me! - and no one has unlimited free time to spend perfecting their mod - least of all me!
The bigger issue is my disagreement with the very forgiving attitude of some people - "you don't HAVE to use the super OP equipment... you don't HAVE to sell the insane amount of added valuable loot and make 60x the amount of gold that's in the original game..." etc. For me, that stuff matters a lot when I evaluate a mod (or indeed, a game). I mean, why not make every attack roll hit for the player, and let the player decide when to miss? Why not play with IWDEE-style Story Mode and let the player decide when to lose battles? Even in such systems, you don't HAVE to win. Right?
While it's technically right, it's also annoying for the player, and making such decisions takes their focus away from the enjoyment of playing the game, out to sitting at their desk to think about what to drop and what to sell, and how to retcon the stuff you decide to drop disappearing, and trying to visually ignore the little glowing pile of invaluable loot that you just dropped, and trying to reconcile this with the character you're playing in your head who should naturally want to acquire and use powerful stuff...
Long story short, that kind of thing is very un-fun and it's just poor game design.
Show me a mod that understands it is a small encounter grafted into the middle of SoA, and has encounters roughly as difficult as those in the middle of SoA, and lets you finish the mod content and continue the middle of SoA still having the experience and equipment that is appropriate for the middle of SoA... THAT is good game design. By all accounts, TDD falls down in this regard.
On the other hand, Fishing For Trouble and the Colours of Infinity mods seems be very good when judged by this measure. I hear good things about Back to Brynnlaw and The Sellswords as well, I look forward to playing them in my next big run. (Which will probably end up being an SoD/EET run, I'm going to stick with IWDEE until all that new stuff gets released and sorted out.)