2019 crf250r engine issue

So had a guy bring me a his 2019 crf250 thinking he had an electrical issue, when your pressed start button just got a loud click and nothing happened. I pulled engine plug out to turn over with socket on the flywheel and motor was locked up, but could turn it backwards until it got to a stuck position again, and then same situation back forward. So I checked timing all was good. Valves were in clearance spec. With valve cover off I rotated engine to free spot and hit the start button and motor turned over continuously. But every couple try’s could find that stuck spot again (even when turning by hand) it sounded kind of loud like maybe piston was tapping head so I tore it down, crank feels fine, piston and wrist pin look fine, havent actually pulled the valves out yet but they look normal from bottom of head. on the exhaust cam the left side that would be the “bearing” under the cam cap had some blackish looking oil like the aluminum was wearing with some slight wear marks on the cam there, nothing major that I would be thinking could stop the engine that hard. I pulled clutch basket out and it didn’t have the Honda explosion, all the teeth on basket gear, cam gears, starter gear, flywheel were all there and in good shape. Bolts on the flywheel were all tight.

Does anybody have any clues or where I should go next?

The guy said this thing died on his buddy while he was riding it and wouldn’t start again