For my cash rate and points award bookings using suite upgrade, Hyatt has not failed me.

On my cash rate, the first email will show the new suite's price but the following email a few hours later always corrected to the original rate.

Yes, it is always a leap of faith on points booking - taking phone agent's words for "all set, you are in a XYZ suite". Then again, I don't recall seeing anyone here run into no suite confirmation when they check in. Until this quirk is fixed, on my trip planner, I do write down date/time that I called WoH. In most cases, they will even tell me who is the front desk agent that they talked to for my record.