Lama Ole’s answer:
That can happen easily. The Tibetans compare the body to four snakes in a tube. The snakes must have their heads at the same level at all times, otherwise they bite each other and become sick. There must be a balance between blood, lymph, black bile, and yellow bile. If the body gets out of balance, then it can actually become quite difficult. We have teachers like Trungpa Tulku who died of alcoholism. The leader of the Nyingmapas was beaten so hard by the Chinese that he became half crazy.
As long as there is a body, difficulties will always arise. If one doesn’t have a body, then it’s impossible to talk to people. So it is simply a challenge one has to deal with. The important thing to understand is the word tulku. It means “illusory body”—that one experiences having rather than being one’s body.