I was having an issue where after pushing my changes to bitbucket, the changesets listed a different user as having pushed the files.
For bitbucket, the commit username has to match your bitbucket username.
As commits in Mercurial are local, we have no way of controlling that you have set your username correctly. It is important for you to set this up in such a way that we can identify your user account on Bitbucket when you push your commits to us.
In tortoise-hg, the username setting is available through global settings->commit