About the strange password error (Unable to login account)

I’m using KeepassXC with Firefox KeepassXC-Browser Addons to login account at 2019-11-06 13:03:20(Logout), then the password does not match the account, but I can login to my account 7 days ago, or can login another account immediately.
Now I regret that I changed my password by email at that time because I lost more chances to find the answer by trying all history passwords. I checked the password history of this account in KeepassXC and Cloudflare Audit Log, nobody changes password.
Is this a bug or a tampering? Will it cause me to get locked out of other websites forever? This makes me worry.

I guessed there are several reasons:

  1. I haven’t updated KeepassXC on the system(through pacman -Syu) for about half a month, which caused an error, but I can still login to other account using KeepassXC and the browser addons.
  2. Invisible bug or error inside Cloudflare.
  3. My local system is not secure, but I have not compromised any serious unsafe behavior.

This may be just a report, the actual reason may always be a mystery.

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