This can occur at any time these days, and is dependent upon what your ideas about it are. Difficulty isn't necessarily dark or negative. Neither are harsh conditions representative of negative activities.
Kundalini can accelerate one into multiple expressions of difficulty and harshness but this is part of what it takes to climb the mountain.
Darkness is needed. And if one labels darkness as travail or trauma then that too is needed. We learn from these scenarios and often faster than from more comfortable experiences.
I feel "The dark night of the Soul" was often, in the past, referred to as a place of supreme difficulty from the many manifestations of phenomena that the student alone, without aid from the teacher, had to come through. This was part of the journey and it was a solitary experience. Just between God and the person. A time of working through fear. It was a point of departure from the training of the student, the place where the lessons and skills were put to the test and one would sink or swim with no time limits.
Without that teaching platform I am not so sure it is this linear for contemporary people who just have it "happen" to them. In some ways it can be organized in that way when the recognition of what one must do to come into balance with in the Kundalini is realized. Understanding fear and surrender and listening to intuition, love, service and forgiveness to name a few. But that realization can take aspects of a "dark night" to accomplish!
I feel Kundalini is a vertical path and it can be narrow and precipitous. It isn't easy. So what part of the path doesn't have an expression of the dark night? It is always there! It is ever present and is a master teacher. Shade from the Hot Sun. - blessings - chrism
We learn from these scenarios and often faster than from more comfortable experiences.