II reservations require EEE points in Hyatt. What was used for the II reservation?
Actually, II reservations can be made by transferring EEE points or CUP points. Key here is 'transferring'. The points are actually transferred. II and RCI are separate entities from the timeshare groups, and both make it clear that all transfers are FINAL. As far as HRC is concerned, the points have already been used once the transfer is made. The estoppel Hyatt generates during a sale never lists any II activity, b/c the only record they have of II is when the points are transferred out or 'spent'. They have no way of knowing if the II reservation has been completed already or is in the future.
The only way an II week could be lost is if the II account itself is cancelled. That 'could' be an issue if the HRC week sold/transferred was the ONLY HRC week in the OP's HRC corporate II account as then Hyatt would no longer pay for the account. Then the OP would need to work with II to keep the account active.
AFAIK the HRC does NOT pay for the II account by the month, but rather by the year, as every year I get a renewal notice for my account even though it is automatically renewed and paid for by Hyatt. Therefore, the account should stay active until the end of the current membership year.
In fact, a guest certificate by the OP would not be needed as the II account remains their's. I have transferred over 20 HRC weeks into/out of my name and the II account/balance has never even been noted in the process. The buyer of the Hyatt week will have a 'new' II account created for them.