I think I've solved it. The board had repetier on it, switching to Marlin firmware seems to have fixed the leveling setup.
Unfortunately I'm now having issues with the print head being too low to lay the 1st layer after levelling.
If you submitted to support, or put it up on GitHub, we can include it in the release and also you will get a $15 store credit to matter hackers.
You will need to export them as two separate STLs and then compline them in Cura. STLs don't have separate objects in them. You can also export it as an AMF and import that into Cura. I don't know how to assign materials in Cura but you will be able to export the separate bodies from MatterControl.
The retina problem is fixed and the build has been updated. The normal download should be working well now.
Outstanding Items (Update early next week):
Not signed by Apple (you will need to go into settings to allow the installation)
Uses 100% of one core
Please let us know any problems you find. We will be updating this rapidly until we get it very stable on Big Sur.
Update to driver problem!. Just done the latest Windows 10 update (version 20H2) and also chose all the optional updates and my Ender3 v2 printer is now recognised and working fine with Mattercontrol. !.
@larsbrubaker thanks! The only place I could ever find was after already installing MC. There was even a forum message about that exact things some weeks back and the only mention was in MC.
As for the profiles issue - it affected all my slicer profiles - solid, 35% file with different bottom and top solid areas. I was able to fix it, but only after I figured why my prints started shifting.