Realracingguru: Do they do this on purpose with obsolete clubs so you have to replace them?
No, what you're experiencing is most likely VEM (Virtual Equipment Model). WGT uses it to make the game play more like real golf. Basically, when you start getting good, VEM steps out of the shadows and kicks you square in the nuts. It makes your accurately mapped clubs go long or short for no reason and your perfectly hit putts will slide by the hole when they should've dropped. Usually it only lasts for a few days and then things slowly go back to normal for a time until it starts over again. It's a constant battle, and eventually you figure out how to play around it when it happens... sometimes.
It's frustrating, but it's part of the game.