Hardware 'Screen shift' issue with IPS-modded GBA

[steval_beaning]

I've backlight modded my old GBA - but I've noticed a strange issue that seems to happen randomly. Essentially, sometimes the screen will be 'shifted' up by 1 pixel (i.e. the top row of pixels will be cut off). Usually, turning the system on and off again fixes this. However, I'm not sure why it is happening and whether there is a way to stop it from happening.
A good example for this is the EZ Flash menu (comparison of normal/with issue):

 

[Lijer]

I did a couple of these mods and if i had any screen problems , i just unplugged and plugged back in the ribbon cable. On one mod i needed to do this 3 times before it worked. Also cleaning the contacts of the ribbon cable can help.

 

[undue_odium]

Ok, so I really don't think this is a ribbon cable issues. I think it's a comparability issue. I have 4 different IPS agb-001's 3 of them are the "one chip" V2 versions and 1 is the 4 chip version. The 4 chip version never "shifts" the "one chips" all do it 50% of the time. Everything else is fine display wise so it's hard to believe it's a contact or seating issue as that would cause a wide range of issues persistent across all carts. I really hope this can be addressed as my "main" system is a "one chip" :'(