Multimaterial Painting doesn't slice correctly

[spikeygg]

What happened?

After painting an object and slicing it, it seems that the paint volume does not make it very deeply into the model. In this animated gif example you can see that I have painted the entire object white and it was originally black. After slicing the very top and bottom layers are solid white but it quickly tapers back to black in the middle. I've run this same test on PrusaSlicer and it works as you would expect it to.

Here's SuperSlicer in the broken condition:

Here's PrusaSlicer in the working condition:

Project file & How to reproduce

1. Open an object
2. I've found that bucket fill on a different color than the default tool's color works for testing
3. Slice the model and see how it decides to organize the tools

Version

2.5.59.8

Operating system

Windows 10

Printer model

Voron 2.4 with Stealthburner G2E and ERCFv2