This is my first time asking a question on this forum and I'm new to Blender, so hello everyone! This is pretty much my first time using ZBrush, Substance Painter, and Blender. Web searches got me a long way but I've hit a snag. There doesn't appear to be a solution online for my problem. The closest thing I found was another post on this site from over two years ago [link], but there wasn't a clear answer then.
My workflow was: sculpting in ZBrush > Substance Painter > Blender. I exported an .obj from Blender back into ZBrush (I love its sculpting tools), and there I sculpted my desired shape key on a layer, split the parts and then exported it from ZBrush as an .obj. I imported it back into Blender and then tried the "Join as Shapes" function. Here are the results. It's not pretty... the mesh basically explodes. I tried applying transformations, but still no good.
Here is a link to my project files. I hope someone has an answer!