I bought a couple of GBA multi-carts for $8 each which have some really good games on them. They work great and saving on multiple games hasn't been an issue at all either. I have however noticed that there is a couple of horizontal translucent lines that scroll slowly downwards from top to bottom on my DS lite screen when playing them though. I don't have this issue with real GBA games nor DS games. They're not too noticable but I can see them once in a while on certain backgrounds in-game. Can anyone shed some light on what these scrolling horizontal lines can be? A voltage issue (similar to NES multi-carts running 5V on 3.3V rated chips) or a grounding issue perhaps?

Edit: Sorry if this is not the right forum to ask this in, I'm still fairly new here and am not sure if this site is strictly for the NES. If so, I apologize. I don't have an account on gbatemp

Pretty sure it's due to grounding or crosstalk. I've had some banged up GBAs do something similar.

Ah ok, so it's possible it's something to do with the GBA portion of my DS lite? It's nothing really major tbh, just thought I'd get some info on why it's doing this. As I've said, this doesn't happen with DS games.
 

Does the issue happen on the top and bottom screens?

I only noticed it on the top screen since that's what I have GBA games set to play on.