Here are three of the four failures. It is not hard to understand why they were failures.
https://www.ammoland.com/2022/04/lessons-from-handgun-defense-failures-against-bears/
The fourth failure was a failure of warning shots to drive off polar bears. No one was injured.
Always take a slow person with you in bear country.............
Very good article. Lots of valuable info and answers many questions.