Just reporting a bug/security concern. I am on CachyOS using Vivaldi. I have autofill turned on, and it will still populate my username and password even when the vault is locked.
If you need additional info, let me know what you need.
Does this also happen if you disable the Bitwarden extension? If so, it is not bitwarden performing the autofill.
@Xplorer4x4 Welcome to the forum!
In your Vivaldi, could you please go to vivaldi:settings/general/ and search for “password”. There, please check if “Save Webpage Passwords” is checked and see if your Vivaldi password manager has some save passwords in “Show Save Passwords”:
It’s disabled just like your screenshot. I found sync unreliable and made the switch to bitwarden which I feel has more flexibility. Hope that helps.
And if you click “Show Saved Passwords”, is there anything currently saved?
Please do not pick and choose which questions you answer. Having complete information is essential for troubleshooting the issue.
Negative……………………………………..
Best not to make assumptions. 
I tried to provide the most useful information I could atm and it came out a bit convoluted. I have no passwords listed(other than sync), so it would seem impossible for Vivaldi to be at fault. Not to mention, Vivaldi itself cannot auto-populate usernames and passwords that I can see.
Okay, then please show us evidence for that assumption, that the autofill would stem from the locked BW account of the BW extension.
PS: First thing [EDIT: I agree with @grb and @DenBesten – first thing would be to deactivate the BW extension to see if autofill stops or not…]
Only if that result would remain ambiguous: Second thing might be to know how the autofill happened (keyboard shortcuts, automatically when you visit the site, do you still see the inline autofill menu from Bitwarden…?). – If you post screenshots, then make sure to redact personal information first. – It would also be necessary to know which other browser extensions you might have installed on Vivaldi.
As far as I can see, you still haven’t answered the very first question that was posed to you:
Totally agree; we try not to do that.
So far, we know that 2 Vivaldi settings are not causing it. Now onto the next step. If you disable the Bitwarden extension, does the problem continue or does it go away?