I've being trying a lot of endpoint, and check the links.avatar.href on them
GET /2.0/user
GET /2.0/users/{selected_user}
GET /2.0/repositories/{workspace}/{repo_slug}/commit/{commit}
GET /2.0/repositories/{workspace}/{repo_slug}/commits
all of them return the default initial avatar image and not the updated atlassian image.
I have found that the site is using
https://id.atlassian.com/gateway/api/me
to get the right avatar image, but Im doing it for bitbucket integration and my users only have a bitbucket authentication.
btw, this is just one blocker of many more I have on bitbucket api. (cannot get a user by mail or email, cannot get user account id from any request to get a user, cannot authenticate with bearer that used to worked, cloning repo sometime not include the previous push and take time to get update it), being succes to have a workaround for for every one of them but this one is a main blocker for me and my company