I had observed this phenomenon, and it's simply a question of statistics and probability...Don't forget that with the new mixed-up bricks from the CBN, you're absolutely not assured to get a radar note in each brick, as it was the case until about one year ago. Remenber that there is 1 radar note per 1000 notes, in any given serie.
Hence, you can get a sequence with many bricks without anyhing interesting (no special number of any kind), and later you can have a sequence of bricks with two, three or even four radars notes in them...On long-term, you should still get 1 radar note per 1000 notes, but they are no more equally distributed among the bricks. They tends to be concentrated in less bricks. Instead having as many radars as bricks, my experience tend to give about two "empty" bricks per "full" brick. But my ratio of radar notes is still lower than one to one (but I have only a sample of 22 bricks over one year span). I don't consider this apparent deviation as really significant, unless I can have a better sample (over 100 bricks). I have a friend who got 4 radars in one brick and he got in many instances two or three radars per brick, but as me, he has also his share of empty bricks.
It's not (yet) the case with BABN, which kept the good "ol'fashioned" arrangement of 1000 consecutively notes per brick, so you're still assured to get at least the radar note, and sometimes, a repeater and with a good dose of luck, the million numbered note (this has appened to my friend last week: he a got the note #5000000 in his brick
.).
I don't believe that there is a sort of "conspiracy", or any kind of "tampering" by the BoC... They don't have time to spend on this issue. Don't be fooled by what you percieve from your point of view... :-/.
So, don't lose hope: the good numbers are still there, they are just more concentrated in fewer bricks... :-/ :-/