I'm using Windows 10, Sourcetree version 2.6.10. At some point Sourcetree kept asking me for my password after I already inputted it multiple times. I've searched help forums, and many people have experienced this, but the number of reasons for this bug are overwhelming. I'm requesting further debugging steps to get me to a clear answer as to why this is happening.
There is a bug in versions 1.16.1, 1.16.2 and 1.17.0 of the Git Credential Manager for Windows that fails to properly store and retrieve Bitbucket Credentials.
Switching Sourcetree to use a System install of Git 2.19 will fix this. We expect to ship Sourcetree with embedded Git 2.19 soon.