AOL's spam filter has two levels.
The first is at the AOL organisation level where anything with repetitive titles day after day can get blacklisted.
Because the post reply notifications are identical every time this is what I was suggesting had happened. Therefore it will affect all AOL users that share the same mailbox nameservers and other ISP's probably adopt the same blocking methods.

That is nothing to do with your personal mail box spamming anything out. It happens before AOL even routes the email to anyone.