Not to jinx things, but I have been free of red frames after several months of "whack-a-mole" trying to solve the problem. It did not magically disappear with any particular software update or change of workflow or hardware. I'm still using my late 2013 MacPro with a Pegasus2 R4. Still using media shot exclusively on a C300.
I am running all of the newest versions of Adobe software and Mac OS.