P30+ many one pixel width vertical line

hi all,
I recently bought a second hand phase one p30+ from ebay, everything works fine and the image looks alot better than my olympus em1. But when I tune the exposure and zoom in, I saw some (around 12) one pixel wight vertical line from top to bottom of the image. I tried different iso same result. May I know is it normal behavior ?
I recently bought a second hand phase one p30+ from ebay, everything works fine and the image looks alot better than my olympus em1. But when I tune the exposure and zoom in, I saw some (around 12) one pixel wight vertical line from top to bottom of the image. I tried different iso same result. May I know is it normal behavior ?