My bike had been sitting for a couple months (yeah, I know…), and I noticed a damp area on the floor below where the water pump is located. I extended a tape measure upwards from a fresh drip drop, and noticed where the leak appeared to originate - from behind the water pump housing.
I hauled my bike on my hitch carrier to the dealer and their inspection determined the cause was a failed “mechanical seal” (#7 in parts diagram). So they replaced that plus several other associated seals and gaskets and fresh coolant, covered under warranty (bike had just under 3k miles). I’m not sure why the seal failed, but keep an eye out for any leaks - even slow drips originating from the engine case, and take care of it promptly to keep it from turning into something major.