Although the picture is there, I have vertical lines scrolling very fast from right to left.
From what you've said and from looking at the pictures....... the "playing field" is not rolling .....just the questionable "lines" that are scrolling from left to right.
The "picture" itself looks to be stable. Which steers me away from thinking it's a sync issue.
In your pictures it looks like the screen is washed out quite a bit.
The black areas aren't very black, more of a white/gray.
You mentioned trying to make adjustments, but have you specifically messed with the brightness, contrast and possibly even the SCREEN voltage on the flyback.
There is also a BLK LEVEL pot (VR201) mentioned in the manual.
Wonder if there is a slight voltage output difference on that Ikari board as compared to other jamma boards. Not uncommon to have to readjust a monitor when swapping boards, even if they are all jamma.
Correct me if I'm wrong in any of my assumtions.