+1 Everybody esp. Jayer who has covered all the bases.
Peekie, if you view your Chase Visa statement & click on items listing the refunds, you will see a negative for points earned. When your statement closes, those will be subtracted from all the points you've earned from spending that month. If the grand total is negative, Chase MIGHT claw back that number of points from your Hyatt GP account.
IF this puts your GP balance into the negative, Hyatt may leave it alone & trust you to earn the points. If not, I hope Hyatt would phone you, not just automatically cancel an existing ressie. To be safe, you can phone Hyatt as soon as it hits & ask them to trust you. Worst case, get a friend to transfer Hyatt points to you to bring you back to zero--or buy GP points.