While working in Altium (ver. 21.8.1) using parts created from the IPC Compliant Footprint Wizard, I've encountered an issue where in the 3D view of the PCB, the created parts appear as a gray box. This box is still dimensionally accurate and doesn't affect the layout or routing of the board, but it is ugly to look at and when pictures of the board are needed for reports/presentations etc. Here is an example of what I'm talking about
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I suspect it has something to do with the footprint wizard, since all of those components were made using that. The vertical connectors pictured were made manually (using a STEP file on the manufacturer's website) and those persist through Altium restarts. I've tried looking this issue up online extensively, but I have not found anyone with the same issue (or I'm not using the correct search terms). The only other forum post I found with it is here, but there are no replies on it (as of today 11/7/2021). If anyone finds a permanent solution to this, please update this page.
UPDATE 2-12-2022: This issue has been fixed in new versions of Altium (22+)