Actually earlier today, I had forgot about this problem. Got the last ball warning, clicked to buy and it told me oops, there is a problem. It made me go to the pro shop to buy.
Originally I thought it was because the balls to purchase were 300 credits and I had 301. But when I purchased in the shop, it worked just fine with the 301. Got the correct number of balls.
So it appears, that WGT has put a temporary fix(if you want to call it that) to the problem.