Researchers at Princeton University have found that the common test of bouncing a household battery to learn if it is dead or not is not actually an effective way to check a battery’s charge.
“The bounce does not tell you whether the battery is dead or not, it just tells you whether the battery is fresh,” said Daniel Steingart(Link is external), an assistant professor of mechanical and aerospace engineering(Link is external) and the Andlinger Center for Energy and the Environment(Link is external).
You learned wrong.
https://www.princeton.edu/news/2015/03/30/battery-bounce-test-often-bounces-target