My VIOFO 119S focused on left side only. See attached photo.
It looks like bad focus calibration or bad quality of optics assembly.
I also have this problem but in my case it is for A119 2017 June V2 stock and the right side is slightly out of focus.
Thanks, requested and received replacement. Now image is sharp and clear everywhere.
I've seen mine go out of focus and a slightly double image on the left side, on a hot day. But on most days it seems reasonably in-focus.