Sorry for the delay in getting back to you on this; I've checked the code and it does indeed limit inactivity email sending to users whose user state is "Valid". This excludes people who have been flagged as "Email invalid (bounced)".
I don't think this is an error with your add-on but perhaps a issues with it and AWS. Using my old email service I had no issues. I think it my be with the validation system and AWS.
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