Done that, I always wblock all drawings out to a new blank drawing, exploded all entities till all i have is lines, arcs etc then use that drawing as a base for all my layouts.
I've also tried cutting and pasting with this drawing, still no dice.
Audit is returning no errors, and when i click on one of the weird lines, it has the usual 3 grip oints, one at either end, but osnaps just don't seem to work. I can find one endpoint, no middle, other end point, not even nearest works.
Is their perhaps a variable to control the endpoint setting?