Sadly this the 'normal' today, seeing how they ,like everything else ,were probably ' Made in CHINA'. Questionable parts, quickly assembled,not properly designed or tested,sold cheaply and resellers not supporting the us, the buyers.
Can you get better LEDs , Yes though they cost more,of course. I have some CREE based units, retail for $300 each that will outlive me. I also have some 35 year old LEDs that are operating 24/7 and still have 96% of their intensity. So you CAN get a quality product..
The dealer / KUBOTA should replace the DEFECTIVE unit if the tractor has low hours ( <1000 )