i am not technician, just sharing here,
have you check the air intake/ filter part ? like my experience is drive through small river the water somehow get in or the air intake part got jammed then no smooth air flow go in so the engine die at the spot, after dry abit or start a few time then no issue again,
or the engine sealing glue already too old (which less likely is this issue

did your bike pop alot of white smoke maybe ?