This is about as simple as it gets but for some reason I can’t figure out why the following is occurring. I started in a woodworking template because I’m drawing in inch increments. I drew a 2" cube and then, using the circle tool, drew a 1" radius circle from a face’s center to an edge (along the red axis). Normally I would expect 4 separate corners that I could push/pull independently - but for some reason 3 of them are staying linked - while 1 corner behaves as expected.
I thought maybe this was an radius segment issue but as you can see in my screen shot the segment totals 24 (or 6 per quadrant), which should put the tangent point right on the cubes edge.
I can work around this easily enough but I wanted to post to see if anyone had an idea what is causing this. Been using sketchup for years and this behavior with such a simple operation has me puzzled.
By the way, even drawing back over the cubes edge from corner to where the circle hits does not separate the surfaces.
Imgur gallery with screenshots here. Keep getting an error when I attempt to embed photos.