Does HR usually become vulnerable to payroll cuts as well?

I just recently got hired as an HR TM, and from what everyone told me, HR TM's usually get 40 hours or very close to that on a regular basis. Hours just got cut for HR and everyone on the team is at 30 now instead of 40. Would this be a regular occurrence, or just because of the time of the year? I have no experience how Target's payroll works and I can't really afford to work less than 40 (left a job where getting 40 hours was practically given) and this would probably make me consider another job if it occurs on a regular enough basis.

Any insight? We work in a busy downtown location in the East Coast and have 4 HR TMs, of which one is a TL.

Thanks.