Prior to the new beta, autofill would correctly put my username in the username field at the top of the Mind and Body login. Now, it fills the username in the 'Create an account' field, and puts in the website URL in the 'Username' field.
This is filling in Firefox 73.0
1Password Version: 7.4.38
Extension Version: Not Provided
OS Version: Windows 10 19555.1001
Sync Type: 1Password Online