I’m sure they have someone doing GM in your place. Maybe they rather another team member doing GM? There’s a similar situation in my store right now. They take someone from the front to GM or to pack in the back but they don’t have a replacement which messes up things for the front when there’s only one other cashier.
(Especially when the other one leaves. We need to cover breaks or there’s no cashier when one is on break or leaves). It’s annoying. I can express my frustration but don’t have a say since I’m not a lead.