Many restaurants this size will close on Mondays; and if they close for 2 days it's usually Sun - Mon.
Throughout my years of the restaurant business many restaurants are closed on Monday it's their least busiest day so this is the day they choose to close to the public that doesn't mean that they're not in there doing other things cleaning appliances things that can't be done during business hours
I guess they need a day off. I'm not sure why it's Monday.
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