If this was recent enough, the log quota should still be active.
1. Check Machine was assigned properly
- Filter on Server via the "DNS Name" found in "Servers" tab
- note: "DNS Name" is not always the same as "Name"
- Filter on Description "A Maintenance Schedule was"
- Then, you should see all the assign and unassign statements for a particular endpoint. Make sure the schedule was added before the window started and there was no removal statement before it started.
2. Make sure there was no exemptions on the endpoint (via it's "Name" in the "Servers") tab
- Filter on Description: "Name"
- Check when the exemption was added vs removed, if it was added before the MW and then removed afterwards, then the machine did not patch.