Weird. I've never had this issue before, so I'll need more information to diagnose it.

What's your server environment... OS / version, PHP version, web server / version, and what are you using to send out mail (sendmail, SMTP, do you have the bettermail addon installed)?

Are you using Cloudflare? Any proxies? Is your IP address connecting to the site stable or does it change frequently?

Also, can I see a screenshot of your e-mail queue from Composr where it sent these e-mails so I can see the timestamps on them? I want to determine if they were all queued at the same time or if they were queued at different times but just didn't all get sent until then.

Linux Ubuntu not the latest I think I recall they have one version behind , PHP 8.0, No cloudflare used on that one default settings on Email using domain email to transfer. My provider DOES switch IPV6 address constantly but it seems this is done only a first boot and connect to the host. (It changes each time I reboot and logon to the internet.) Screen shots in a few and will attach them.