This happens to me too, I’m using 1Password. I have a suspicion the plug-in is involved with this but I’ve not had time to collect evidence yet. Seems to be rare though, I’ve not spotted anybody else with this issue.
I am seeing lots of spinning balls with 1Password on my 2015 Macbook Pro. Even just switching between fields with the keyboard brings up a spinner for two seconds or so. It's a recent thing I think. No other app has any issues.
I don't use any external password manager, only Keychain and Safari and I see this 10-15 second delay every time when adding new password to Keychain since day 1.
