JORN OTH Radar detected MH370?
I'd say that it's unlikely that JORN did track MH370.
Two reasons, firstly I suspect that if they had they'd be crowing about the capabilities of the system to enhance its effectiveness as a deterrent.
Secondly I doubt that with that knowledge, the Australian authorities would have wasted hundreds of flight/seatime hours on the search far to the SW of WA.