Backup Window -Time- Setting Not Followed

I used to have backups starting during some days from 00-03 and also from 17-24 as such:

4-6/0-03, 17-24

This seemed to work as expected and resulted in some clients with backups early in the day and some later in the day. I have since modified the backup time window to just 17-24 like this:

4-6/17-24

With this latest change, the days (4-6) are respected, but I still have clients starting early in the morning. All settings are controlled by the server and server Settings->Permissions do not allow clients to start any backups.

What am I doing wrong?

Thanks.

Bump - Hope someone can tell me what I am doing wrong here.