That block is a negative block, reducing the height of the model. The original model is quite tall, with the extra height I removed with this negative block being just black vertical bits that I don't think looks very good. The photos I included are of the print with this negative block in place which look much better than without the negative block. I would have preferred to have cut the model instead of using a negative block, but I had already spent a lot of time coloring, and Bambu Slicer loses all coloring when doing a cut: https://github.com/bambulab/BambuStudio/issues/750 So the negative block was the best solution, and produces the same result as if a cut had been done.

@craigandrews Totally makes sense. Ive had the same problem when coloring models as well. FWIW, on a 16 core machine it would come back from slicing in a reasonable time (so long I cancelled it). Perhaps a bambu bug/issue they may fix but that was the issue I encountered. I printed them without the block and makes sense why you trimmed it down. Everyone loved them just the same. Thanks for the model!