Water damage on the led board, that's the culprit. Don't wash your bike with pressure washer. Actually, don't use water near the battery until you solved the problem. You're risking more damage or possibly thermal runaway. There's a recall for M1 batteries with this problem. Basically, the sealant at the button interface is failing and must be reapplied.
Thanks for reply
i agree with you on why the leds are feiling, not that I use a pressure washer, but this battery is not on the recall list so specilized dealer are just saying they have seen the dim leds and it is not effecting the battery. Am pushing them as I am trying to sell the bike.