Some shots outputting backwards to Quicktime

Just output a motion picture from its 4k timeline out to 1920x1080 Quicktime. The Project is 98 Mins but broken into 3 separate projects to avoid any lag. For the past few mos the project has gone swimmingly with practically no crashes or problems, of course working with PROXY's to help avoid that. I installed the Swiftly Studio transition program a couple weeks ago, which too has been a great tool for some cool transitions. I output the film about 3 weeks ago with no issues -  all good. Upon outputting yesterday and watching the film back burned onto a bluray to enjoy on our big-screen TV, several shots were backwards (or horizontal flipped as Adobe calls it). These shots had NO effects on them and were only flipped on the steadicam shots used within the film (but not on all of them). I went into the project files and all these flipped shots were correct within their respected timelines BUT "flipped" in their quicktime outputs and no matter what I do, I cannot change those shots from outputting to Quicktime incorrectly (backwards). I've tried it without the Swiftly files too (again those shots have none of the effects on them anyway and those that do, output just fine). The only thing I can try for my upcoming screening is going into the quicktime files I output while inserted/dropped into a new project file and "Horizontally Flip" them back before converting once again before watching on bluRay or any other format. I have tried outputting the project in its native format (4k) to see if that would help, but it doesn't. Any thoughts as to what in the heck is going on here? Im stumped. I have a 4Ghz Intel Corei7 iMAC late 2015 Build

Thank you!