Parasitic Drain, 2014 Rocket III Touring - Mystery: Multimeter shows zero draw with the key out

I just rolled the bike out of winter storage.
Topped up the battery with the tender every week. It was on the Tender until Saturday, when I took it off. Two days later, barely rolled over 2 pistons.
Like others, this bike USED TO behave normally.
Battery lasted 5+ years, it could sit 2 weeks or more, fire right up.
Since this BS started, 5 years ago, I replaced the battery 3 times, US made AGM.
Same thing, no measurable draw.
I'm gonna check the relay as suggested by Frazier.

I see this thread is still alive. So, here is my advice, based on my experience.

If your healthy new battery is draining "for no apparent reason" something is drawing power from it and you do not have the equipment to measure this or the equipment you have is faulty.

The amount of sparkies I know who try to measure milliamps on their multimeters and get 0mA, is probably 9 out of 10 who have blown the 1a fuse in the multimeter.

Most multimeters need the leads to be changed when changing from Volts/Resistance to Amps. Good meters have a lock out system that prevents changing the dial to amps unless the leads are in the correct position. Cheap ones don't. Often, when testing, it's easy to forget that you are still on amp measurement on the multimeter and you want to measure voltage. You won't even know the fuse is gone as there is no spark, no flash no bang. The fuse just blows inside the multimeter and your low amp measuring functionality is gone.

When measuring for a parasitic drain, I remove the negative terminal from the battery and connect my multimeter in series between the negative terminal of the battery and the negative cable. I start off with the highest amp range on my multimeter and slowly work my way down. As I am a process instrumentation technician by trade, where 4 to 20mA is the standard output for most devices, my multimeter can easily measure micro amps.

I repair CNC machinery, for the last 35 years.
I certainly have proper test equipment, and know how to perform the test required.
The fuses are not blown, and I carry spares.

But hey, thanks for playing!

FWIW, I remember in the “old days”, batteries would discharge left out, not connected to anything - and it was “known” that batteries left out had to have caps on the terminals, and be lifted off the floor, often on 2 x 4. I would guess, if that somehow were happening with the the Rocket, it would be difficult to nigh on impossible to determine the source, and twice daily checks of the voltage would itself be a kind of draw, and would provide data for the curve. I know I leave my bikes on automatic trickle chargers indefinitely, have done so for a number of years, and just assume my bike will start no matter how long — to a point, of course — it’s been sitting.