When MB does not retrieve the correct artist data...here are a few steps to try that have worked for me:
1. Verify that the artist name you provided is spelt correctly.
e.g Michael Jakson
won't retrieve Michael Jackson's
2. Check if the name you have is one which is recognized in the music world.
e.g Michael Joseph Jackson
(his full name) won't retrieve Michael Jackson's
3. If the above is correct and MB still brings up someone else's info, then that means
your artist is not available on the platforms (Last.Fm and Wikipedia I think) which MB gets its data from.
4. If there's more than one artist with the name you provided, MB will list all of them for you and in which case, you would have to manually edit/remove the other irrelevant artists.
So if after all this, you're still not satisfied with the retrieved results, your only option is to look for the information yourself. Search it and copy/paste it into MB.
@Stgo, I found this
regarding Gus Mancuso, copy that description and replace the incorrect bio that MB is currently showing.
It's also important to note that it's not a bug when MB retrieves the "incorrect" info. There would be valid reasons as to why that happens. Some of them are mentioned above.