I can't find the repo from the screenshot, but I had the same sort of thing happen to me. My bitbucket user is "tshatch" but I'd commited things as "thatch" for ages, and they link to another user. It looks like "other alex" has the bitbucket username "alex".
Initially, Bitbucket was extremely eager to associate a commit with a Bitbucket user. If one were to commit a changeset with `# User bob` in the metadata, this'd match to the Bitbucket user named "bob", which may or may not be correct.
We realized that this was causing problems, so we now associate changesets with Bitbucket users based on e-mail addresses. This avoids erroneous matches.
Some users, of course, had been taking advantage of Bitbucket's loose matching and did not include an e-mail address in their committer string. Affected users should do two things:
Update their ~/.hgrc files to include something like `username = David Chambers <email@example.com>` in the `[ui]` section. This will ensure that future commits are correctly attributed.
Add committer aliases to any repositories with unattributed changesets to fix past commits.