Exporting 4K up to 25P only & green line at the bottom

I have raw footage recorded in 4K/50P.  No problem editing on Virb Edit, but exporting I found it can only go up to 4K/25P.  Not really a problem, in fact I welcome an excuse to record to smaller video files in the future.  But then I also noticed a green line at the bottom of the resulting video.  I suppose that's related to my raw video recorded at a higher FPS which Virb Edit cannot export.  It won't be a problem since I will go down to 25P from now on, but I want to bring it up in case anyone else encounter or avoid it, and for Garmin to fix if every the are going to support 4K/50/60P exports in the future.

Here's the exported video