The holes being filled in is a known bug. It's listed in the notes when you open the application too.
If you are using PrusaSlicer then you should always export to 3MF format. This will fix the misalignment of the numbers you are seeing. If you export from SimplyColor3D as STL then you will need to align the different parts of the model manually, which is difficult to line everything up. 3MF solves that problem because all the different pieces stay in the correct relation to each other.
If you can attach the exported OBJ & PNG that you painted in SimplyColor3D I can take a look at the numbers.
I'm getting timeouts on model split right now at noon EDT, even after refresh. The same model split earlier in the morning with no problems.
Working now, thank you.
only V1 is paused. You still have access to SimplyColor3D 2.0