Description of problem:
Even with https://bugzilla.redhat.com/show_bug.cgi?id=2044314 fixed, there are some cases when katello wrongly calculates list of errata to send in email notification.

Particular example: RHSCL 7Server prior RHSA-2022:5759 released (i.e. have CDN content prior 2022-07-28) and after he errata released. Syncing the repo means "Added Rpms: 22, Errata: 1" but notification mail to contain 146 errata.

Explanation provided in https://bugzilla.redhat.com/show_bug.cgi?id=2102867#c2, internal reproducer available at https://bugzilla.redhat.com/show_bug.cgi?id=2102867#c4 .

The #c2 also suggests a potential fix.

I am raising a new BZ since I cant reopen the https://bugzilla.redhat.com/show_bug.cgi?id=2044314 one.

Version-Release number of selected component (if applicable):
6.11.1

How reproducible:
100% with reproducer per https://bugzilla.redhat.com/show_bug.cgi?id=2102867#c4

Steps to Reproduce:
1. Have RHSCL repo with metadata per https://bugzilla.redhat.com/show_bug.cgi?id=2102867#c4 , sync it
2. Update the metadata to the newest, sync it
3. Check errata mail sent and also the postgres queries from https://bugzilla.redhat.com/show_bug.cgi?id=2102867#c2 .

Actual results:
3. Mail with 146 errata sent, psql queries like per https://bugzilla.redhat.com/show_bug.cgi?id=2102867#c2.

Expected results:
3. Mail with 1 errata sent only.

Additional info: