Membership 2 Pro and Pro Sites notifications mess up

I have noticed that on a secondary subsite (not primary), when I turn on Pro Sites on the primary site on the multisite then it seems like those members are getting Pro Site email notifications too? Strange.

I have Membership 2 Pro with paid members on a non-primary subsite.

How can I stop that so that only those who checkout on the primary site Pro Sites checkout get them and not the secondary subsite that has a Membership 2 Pro plugin members?

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