"Definitely had this issue, spend ages fault finding and eliminating other things trying to find it too.
Short story, changed cable, solid video since then.
Fixed. Q.E.D."

"That is a HDMI cable problem Chip.
I saw your post on 3DR Pilots forum and answered there as well.
But for anyone else who has this problem
A quick temporary fix would be to discon/reconnect the hdmi cable inside Solo, that might get you working…"