All my (Total 4) print surfaces show the same general pattern - as per pic. A bow along the centre line. Same shows up even if I rotate them,
I suspect that part of this must be to do with the frame or heated bed?
Any thoughts?
I wouldn't touch it but basicly if you want to know why, its either the bed that is bowed down in the middle ever so slightly or the gantry is going up a bit, but since you rotated it its the bed.