I'm still stuck with the horizontal lines in the captured image on my 490ex. I tried to experiment a little bit using different OS and drivers: RPI3, RPI4, Ubuntu 16, 18, 19, Raspbian buster, etc.
Found only when I use cloudmakers Atik driver 1.17 (which is pretty old already) there're no horizontal lines.
When I use Cloudmakers 1.30, libatik (the new driver) both having the horizontal lines, at different position s though.
Short captures like 10 sec the lines are visible after autostretch. At long exposures like 300 sec the lines are not visible but I didn't stack them so I don't know if that'd affect the final output or not.