I'm trying to confirm a suite upgrade at the GH Beijing. Hyatt CS is stating that the only suite available for upgrade is a Club Grand Suite King, when plenty of of Club Grand Suite Twins (and plenty of Grand Suite Twins) are available.

Could this be correct? The terms state:

"Complimentary Suite Upgrade Awards are only valid for standard suites, defined as each participating hotel’s or resort’s introductory suite category, and are subject to availability."

There's nothing about hotels being able to restrict by bed type beyond picking the introductory suite category.