Error 'ssh-agent' failed with code -1: System.NullReferenceException in 3.4.15

Hi, I have the latest SourceTree for Windows (version 3.4.15) and using Git standalone version 2.41.0.windows.3. I am using Windows OpenSSH for authentication.

SourceTree gives the following error:

This happens:

• - every time SourceTree is opened
• - every time I close the Tools -> Options window
• - every time Tools -> Launch SSH agent... is clicked  (so I assume is OpenSSH related)

This happens  since version 3.4.8 (see https://community.atlassian.com/t5/Sourcetree-questions/Error-ssh-agent-failed-with-code-1-System-NullReferenceException/qaq-p/1964089)