Applying textures breaks model?

This one has me stumped. This all previously worked just fine but all of a sudden, it just doesn’t.

I’ve got a model that slices with no issues (pic 1). Note the curve of the edge highlighted in red and how it slopes smoothly.

I want to create a region within the part that follows the surface contour but is slightly below the surface. I make a sketch which creates a border inside the part, extrude that sketch, move the extrusion into the part and do all of the subtract functions to get what I want. I load that result into BumpMesh and apply a texture to only the area I want. Again, no problems (pic 2).

Now (and again, this has always worked before today) when I import that file from BumpMesh into the slicer, it cuts off part of this whole edge. The edge now has a 90 degree wall instead of the smooth curve (pic 3)

I’ve tried exporting my original project as a step and performing all these steps only to that file and it does the same thing.

Why is adding the texture to the inside of the bordered region cutting off part of this model when I slice it when it never did before? There’s a weird tesselated region in the slicer along that edge outlined in black in pic 3 that is clearly the missing part, but I have no idea why it’s subtracting that part.

It does the same thing in Qidi Studio and Orca. When I create a totally different object and go through the same steps, it works as expected. What is it about this particular model that is causing this?

Any help is much appreciated.