I'm shooting in movie mode so the Live View setting is permanently on with no option to change that.
I switched over to Manual mode to test it and the weird lines / green effect started as low as ISO 8000.
I haven't but I will do now. I was just checking just in case it was something that I was potentially doing wrong.
Thanks for your help.
Thanks for your comment.
I am indeed having trouble at the other frame rates too but only at high ISO's and quite sporadically.
The 120fps issue was more apparent as the ISO was 4000 which in reality should be no problem for the A7s surely?