I am having a problem with engine

During my last ride approx 8 weeks ago I was cruising in the country at 60 mph. For no reason, ie no lack of fuel etc, the engine just died. I coasted to the side of the road and then tried to restart it. Bang, it fired up perfectly and went straight to a normal idle.
I then selected first gear and gently started to ride away. The bike would not rev past 2500rpm before it died again. This occurred another 5 times before I gave up and had it towed to a shop for repair?

8 weeks on and the bike is still in the shop and still doing the same thing. All the electrics have been checked and appear okay. The stator, which was replaced approx 3 months ago, also appears to be okay as well. There has been speculation by the shop that the use of a non ducati stator could be a cause. Apparently 10 suppliers/mechanics said no, one said yes. What to do with that information I don't know.

The fuel pump and filter have been pulled apart and the filter replaced. The old filter had a lot of crap in it, but the mechanic doesn't think it is enough to be causing the problem. The pump was inspected and bench tested, where it worked fine.

Now they are going to pull the new stator out and see if there is a problem with it.

If anyone has experience or theories I would be grateful for them being shared.

Thanks in advance