When I used Creality as slicer, it just started to print object, but since changing over to using Cura as slicer, it prints a straight line on the left of bed first, then only starts printing the object. is this normal?
Yes, this behavior is normal when using Ultimaker Cura as a slicer for the Ender 3 printer. It inserts a "priming line" at the left side of the print bed before starting the actual object printing. This priming line helps ensure proper filament flow and adhesion before starting the main object.
