So far I completed the ts sig twice (1 x Thurgadin, 1 x Maj'Dul) to see how it works. I didn't face any bugs at that time, lucky me. But Part IV was the worst part, way harder than the other ones and the reason why I'm so reluctant to do it again. Now I just run Part I - III to get my alts on lvl 110. Part IV is a pain in the butt and the rewards ain't worth it. The Familiar is nice, the bag too but nothing I really have to have.