Maybe the issue was elsewhere; maybe with the motorcycle. Maybe they didn't do a proper load test. Maybe the battery had no capacity. And if it died while riding, I have to wonder why.
That is exactly what I thought when the battery failed while I was riding. I assumed the computer had failed, since I wasn't getting any dash lights.
I had never before had a battery on a bike or a car fail while the engine was running. It always happened when I attempted to start it. I have a couple reasons to think there was nothing at all wrong with the bike.
The first reason is that I called a BMW dealer and talked to a very experienced service manager and described exactly what happened. He immediately said he was over 99% certain that the only problem was the battery, indicating he had seen the exact symptoms many times on many models. He explained that the ignition system is driven entirely by the computer and the computer shuts itself down automatically when the voltage drops below a certain level. That explains why there were no dash lights or any other activity.
The second reason is that the bike has run without any problems at all for nearly a year and a half since that happened. It could be that they did not do a proper load test.