Something's up with Starmaster...

I'll be playing and suddenly the screen will roll and whatever enemy was on screen (meteor, starbase, ship, etc.) will be in another spot. On my Coleco XM1, sometimes the sprite will appear in three different places. My heavy sixer and my 7800 don't do that, but they will have the screen roll thing.
I bought another copy of Starmaster for a buck, and it does the exact same thing. Carts and consoles are all clean and working otherwise.

Anyone else notice this?