Hyatt reservation 3 nights but only 2 awards were used
 

Something strange happened to my reservation. So I had cat 1-4 3 free night awards and Hyatt helped me to book a reservation to use all 3 in one booking so I don't have to switch rooms. Fast forward I had to change dates, so Hyatt helped me change it for different 3 nights on different dates. I looked my profile tonight and it shows that only 2 awards were used and I have 1 more left (they combined all 3 awards in my profile). I double checked the modified reservation and it indeed shows 3 nights using FREE NIGHTS.

I’m unsure whether I’ll have issue with checking in or not given only two award nights were used for a 3-nights stay? Or I just wing it and and wait until the day of check-in to sort out any issues. Thoughts?

Just wait until you check in. And don’t use the “spare” award before then.

Could the hotel be offering buy two get one free on stays paid with money? That could cause a confusion/error on your reservation.

It is likely a human or IT error. Just check-in and enjoy your stay, and wait until your stay posting on your account. If the award still there, it's yours. :)