Unable to Remove Support-like Features in Infill

[TheOneTrueRazor]

Description of the bug

I’m currently printing 12mm tall Christmas ornaments on my 5-tool XL. Layer height is .2mm, infill is set to 10%. I use single color/tool up to the 10.6mm height. Then PrusaSlicer begins to use the other tools for the multimaterial painting features.

Throughout the slice, multiple “towers” are made in the infill. My assumption is that they are there to support the details (nozzle paths) on the top layer.

This behavior appears on multiple projects similar in design.

Project file & How to reproduce

In an effort to remove them, I attempted to print a solid layer just before the multimaterial painting. That did not solve my problem, in fact even with a 100% model infill, these features continue to exist.

While I understand the need for them with lower infill, I expect their numbers to decrease as the infill density is increased and completely disappear when the infill is 100%. They increase print time, add complexity to the print, and cause top and bottom surface imperfections.
Archive.zip

Checklist of files included above

• Project file
• Screenshot

Version of PrusaSlicer

2.8.1

Operating system

MacOS 12.7.6

Printer model

XL 5-Tool

[u89djt]

#13685
(Fellow user following the hub)
TLDR: Lots of mesh bodies with mismatches where they meet at the curvy svg lines. Doesn't seem like a bug.
Taking the svg you posted here
https://forum.prusa3d.com/forum/prusaslicer/svg-multi-material-painting-help/?language=pl
...and building in Fusion 360 with added outlines and a yellow border to mimic your project model, I get the following for comparison. (Plus an appreciation of how much work you put into it.)
Your original is bottom left, and a copy of it with the painting deleted is above. My fan art is on the right, and then with all colours set to grey above it.
rebuilt Hornets.zip

My model is split into part groups for each colour so it can have a definitely solid base.
We also see the effects of mesh surface mismatches in the topmost array of colour parts in the all-grey version of mine.

But not in the main solid body of the base. The view is of the layer where the bridge infill for the void perimeters are placed.

It seems like the problem is that the approximation introduced by meshing causes voids between bodies that the slicer doesn't extrude through.
You can juuuuust see some of the near-misses:

[u89djt]

This is the cleanest version of your original mesh (starting with that, not the svg) that I can make by sequentially subtracting faceted parts from a merged whole. It still glitches in two locations if it's loaded as a step file (an ensemble of abutting faceted bodies). Instead of continuous towers, there are islands above each other that don't appear at the top surface.
hornets clean.zip

If you set the slice gap closing radius to 0.005 the glitches in this project disappear. Not in your original project, sadly.
I've run out of ideas for the moment.