I have used infusionsoft and memberium plugin in wordpress.
When I sign up with free plan then user and password is generated properly and sent through email.
But when I sign up using paid membership plan then password is not generated and sent email without password.
Website Url: https://growthskills.staging.wpengine.com/pricing/
If you want any details from my end then please let me know!
Can you please check this issue.