In the moderator dashboard, there's an option to record yourself as absent / inactive. I did that a couple of days ago, but now I'm back from a holiday and wanted to report myself as present. There seems to be a copy-paste error in the following text (emphasis mine):
By default, you will only be marked as absent for the current site
That's the same text as in the Absence Reporting dialog. If I understand the functionality correctly, "absent" should be replaced with "present".