Battery is toast.
Dealerships install the batteries. Dealerships have batteries sitting on shelfs for sometimes months to years. Once a AGM battery drops below 12 volts it starts to deteriorate. Then they simply do a quick charge to get the bike out the door. Some people including myself have had zero issues with batteries on these bikes. They are quality batteries, but because they sit uncharged at some dealerships, the go bad and you get stuck with them.
During riding season, I never put the battery on a tender. But I also make sure to ride no less than once a week.