Hi, I have a strange issue with my Kubota GR1600 Mark 2. For 20 mins or so it works away cutting going forward but as soon I press the NMR switch and start to reverse, the blades cut out and the tractor dies. If I wait a minute and start again going forward - the blades reengage and everything works fine - even in reverse with the NMR switch depressed the blades will keep working!!. But this can happen again 15 mins later or so!. It cuts out 3/4 times every 2 hours or so - any guidance or help is greatly appreciated. Thanks.