Hi @lmacri,
As with Nergal, I don’t experience the same issue.
After looking into this, there are a few things that can contribute to this kind of delay, and it’s likely a combination of factors on both the sending and receiving sides:
On the forum/sending side: The CCleaner Community runs on Discourse, which queues outbound notification emails. If the platform’s mail queue experiences a backlog, notifications can be held and released in bulk — sometimes days later. This would also explain why the delay appears in your profile’s Notifications section too, as you noted.
On the receiving side: Email providers (and corporate mail filters like Microsoft Exchange/Outlook) increasingly scrutinise bulk notification emails from “noreply” senders. It’s possible your provider is briefly holding the message for spam/content analysis before releasing it to your inbox, a process sometimes called greylisting. As Nergal suggested, this would be unique to your mail setup, which is why not everyone experiences the same delay.