Virb Edit export upside down and mirrored

Yes, same here with my MacBook Pro with Intel Iris graphics. On my seven year old MacPro it worked properly because it didn't offload the processing to the graphics card (probably too old for 4k), but instead spawned off encode/decode processes (which chewed up a lot of CPU). I tried inverting the video in VIRB Edit (under the Editing tab in a project) but, while it correctly inverted the video, the G-Metrix were both upside down and mirrored, since inverting the clip doesn't apparently invert the overlay. If you look at the exported upside down video in Quicktime Player, you can use "Flip Vertical" in the Edit menu to fix the video, but you can't save it as a 4k video. I just finished reexporting the video I was working on with VIRB Edit and am going to attempt to use ffmpeg (installed using MacPorts; I live in the command line most of the time) to do a lossless vertical flip and see what happens. ffmpeg is also useful to cut lossless clips from an exported video.

Added later: so ffmpeg -i input.mp4 -vf vflip output.mp4 indeed fixed the video, but it may have decreased the video quality (27 Gb vs 40 Gb for one hour of video) and stripped the audio. So in the end this is going to have to be fixed in VIRB Edit.

The just released VIRB Edit 5.1.2 fixes this problem

VIRB Edit 5.12 does _not_ fix the issue for me, the export video still upside down.

I use iMac OSX 10.11.6