Yes, Muse forms do attempt to queue an email message to recipient@example.com to try to ensure that PHP forms will work on your web host. Most hosts ignore these emails because example.com is known to be a good address to test things out.
Unfortunately Muse doesn't currently provide a way to opt out of these test emails. Note they are only sent as part of the publishing process when Muse uploads the form and verifies that it works.
We'll consider adding an option to avoid these test emails, or reduce the frequency(so they're less of a bother) in a future version of Muse.