Having a similar issue: I have 63 WPF in throwing and 6 PT. When I use war darts, I get a message at the beginning of the round stating "Your proficiency in throwing weapons is too low".
I am clearly exceeding requirements for war darts and can still use them. However, they seem VERY inaccurate.
Is there a WPF requirement for each throwing weapon now? And if so, what is it?