my pro had same problem for many months ... I finally pulled the glass off and found that my shooter lane guide had a small indention on the vertical edge where ball leaves the lane - I presume this was caused by balls striking the metal edge. I took a small metal file and filed the dent/ridge flat. ball has launched correctly ever since. did not move or remove or tighten any screws - 2 minute fix that I should have done months ago
sucks being lazy