Thanks for the reply mitcorb...
I was messing around with it today, trying to duplicate, and instigate the undesired behavior.
It just appears to be "Hidden Geometry" becoming unhidden... Usually when I hide something, to get it out of the way of what I am working on at the moment, I'll click "Unhide All", when I'm finished. The randomly created hidden geometry, appears to just be SketchUp doing it's thing, behind the scenes, when edges, faces, and points, cross that forbidden "proximity line", where SketchUp no longer offers you a choice of precision - it just decides to do what it wants.
In future releases, they really need to crack down on the math in this program... I'm getting sick of the same root problem, that seems to know no scale, or visibility. If any two edges, points, or faces are close enough to "snap" into another form, in the free version - then there really is no point in trying to market a pay version, which is essentially the same program, and same problems.
Thanks again... 😉