More information is needed here. Are you right handed? Is your bow cut to center or past center? What draw weight is the bow? It's possible that your shafts are too stiff and are hitting the riser, especially if it is not cut to center. I had a similar experience with a "50s style" recurve that was not cut to center. I had to use full length shafts with heavy tips to get the arrows to bend around the riser. Since lightening your tip, essentially stiffening the spine, didn't help, I'm guessing this may be your problem.
If you have an uncut shaft, load it heavy and give it a try.
Hope this helps.
Russ