ssh support from 1password breaks github access

I cannot complete my work because the SSH agent and 1Password fail to work properly.

I've tried backing out without success.
1. Edited ~/.ssh/config
2. Edited ~/.gitconfig
3. Removed a key from GitHub and moved it into a .hide directory
4. Removed references to github.com from the known_hosts file
5. Kill processes with ssh-agent in their name

I thought I understood SSH integration, but apparently not, I don't, and I really don't have a clue.

I use git in two ways:

1. iTerm2 command line via bash or zsh
2. Tower application

Neither works... :-(

Example error:

% git commit -s -m 'Implement issue #507'
error: agent returned an error

fatal: failed to write commit object
% 

It may involve adding a new SSH key on GitHub, which I have subsequently removed. Unfortunately, the error is still there. I've tried killing the ssh-agent. It might also have something to do with allowing 1Password to configure things for me.

Weirdly, a few repositories seem to work. This really has me stumped.

I tried a message to support, but have not received a reply to my knowledge. At least a search of email doesn't reveal anything.

1Password Version: 1Password for Mac 8.10.4 (81004032)
Extension Version: Not Provided
OS Version: macos 13.3.1
Browser:_ Brave (not applicable though)
1password cli: op --version 2.17.0
Git version: 2.40.1
SSH version: OpenSSH_9.0p1, LibreSSL 3.3.6