MR policy says:

Guaranteed Concierge/Executive/Club Lounge Access* at JW Marriott, Autograph Collection, Renaissance Hotels and Marriott Hotels & Resorts during normal hours of operations: Monday to Friday. Outside the U.S. and Canada, continental breakfast is available 7 days a week. For JW Marriott, Autograph Collection, Renaissance Hotels and Marriott Hotels & Resorts without a Concierge/Executive/Club Lounge, Elite Members will still receive a complimentary continental breakfast for weekday stays, Monday through Friday; simply show Membership Card and room key in the hotel restaurant.
*Not available at resort locations.

but rule # 8 says:

Local policy may prevail over Rewards Program standards at hotels, and some Elite Membership benefits may not be available at some locations.

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I would call Plat line and complain. I had this exact problem at Anchorage Marriott. I escalated the issue and it was resolved in my favor. This was 3 years ago and have not been back, so not sure how they handle it now.