It's seasonal. Now that it's summer and hot, thier bodies tell them they don't need as much insulation, and they remove some of the "blanket" to keep thier body tempature regular.
My cats are doing the same thing right now, it's disqusting and a big annoyance, but it's something we have to accept I guess--I don't know of anything to help the problem. I've been brushing mine a lot more in the hopes that I can get as much of the hair as possible into the brush and not on the furniture and everywhere else imaginable.
The Original Male Kitten.