The seam only appears on AGA amigas in WinUAE and FS-UAE.. But it displays slightly different behaviour if the copper is an OCS friendly or AGA one.. (its a black line on 24bit skies and a crease in OCS ones).. If I set it to just emulate an A3000 they don't appear. (you can replicate it in CMO latest build by pressing 3 and going to the right long enough to go through two teleports.)
I don't know if this happens on every map or just incredibly wide ones, but at about 840 pixels down there's a seam in the copper sky.
https://youtu.be/3Y1A7Q7mwrk
The seam only appears on AGA amigas in WinUAE and FS-UAE.. But it displays slightly different behaviour if the copper is an OCS friendly or AGA one.. (its a black line on 24bit skies and a crease in OCS ones).. If I set it to just emulate an A3000 they don't appear. (you can replicate it in CMO latest build by pressing 3 and going to the right long enough to go through two teleports.)