I just got off the phone with Chris who was an Accounts Manager from I believe the US Priority Club team. (They never called me back so I had to ring them again.)

He was able to manually process my request for a Points + Cash option, so he charged me $40 to buy the 5000 points but left my reservation as it is.

I advised him that I was not the only person with this problem and he said they WERE aware of the problem as of yesterday but they were not sure when an update would be available to correct this problem.

My best advice is to leave one points-only reservation as it is, call their customer services line, ask to speak to an Account Manager who can do this manual purchase and worse case scenario, ask to speak to 'Chris'.

Best of luck everyone!