Possible water/corrosion in the control head. Rubber buttons crack and water enters, ruining the unit. Gotta be that or the unit itself. Be aware of the issue with matching software when you replace it. Delayed feedback and parasitic drain both indicate it's not shutting itself down like it should. Try disconnecting the battery and then touch the cables together to discharge the memory. You might get lucky.
Way, way back in the day, this was a recall situation on ole Toad ('99) and until the dealer could do the warranty work, I wuz advised to turn off the radio before turning off the bike. I don't remember the final fix - whether or not the radio wuz replaced or a software update. Butt the battery discharging stopped when I remembered to turn off the radio first. HTH.
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