Around the age of 4 - 6 weeks Bengal kittens begin to have longish hairs protruding from their coat making them look very fuzzy. It is an "ugly duckling" stage and the kitten loses contrast and its coat takes on a dull appearance and can look blurry.  It also makes it very hard to get good clear pictures of patterns if not impossible.  When the kitten is around 12 weeks they shed their fuzzies and emerge as beautifully clear coated kittens as their pattern shows through beautifully.

Below are some examples of the the fuzzies and the changes kittens go thru:

 
Top pic taken of Amazing Grace at 2 weeks

Bottom pic at 2 years

Top pic taken of Amazing Grace at 2 weeks

Bottom pic at 2 years