Pro Sites does not assign level when using PayPal Sandbox

When using PayPal Test Mode (Sandbox), user accounts and sites are created through Pro Sites, but Pro Site status is not properly assigned to the account. I'm getting the message "{site}" has never been a Pro Site with the following transaction log:

2017-11-08 3:18:22 ??	PayPal subscription IPN "recurring_payment_profile_created" received. -
2017-11-08 2:06:14 ??	User creating new subscription via PayPal Express: Subscription created (www.******.com Pro: $60.00 USD each month) - Profile ID:

IPN is setup correctly. Staff in chat tested their "known good" credentials and replicated the issue.

Subscription Information