SOLVED: Error message "Radius to end of arc differs from radius to start of arc"

NOTE: this error message apparently can have more than one cause, so there can seemingly be more than one solution, which also means that any given solution may not work for everyone, as their cause may be different.

In my efforts I searched for, and found, multiple threads about it, such as this one:
forum.linuxcnc.org/38-general-linuxcnc-q...-arc-differs-etc-etc 

...and others. I read them all as best as I could understand.

I tried decreasing tolerance on the Fusion 360 side, and also tried increasing tolerance on the LinuxCNC side (by adding definitions to the INI file). No luck.

I was outputting a very complex cut job from Fusion 360, using the post processor called "PlasmaC / Plasmac."

In my case, the solution was to uncheck "MergeCircles" under "General" on the "Post Properties" dialogue box.