[1.1.1] OSX 10.11: A huge Delay after running a script some short time

1. version of Sikuli : 1.1.1
2. OS : Apple OS X El Capitan version 10.11.4

3.4. Hi, The link below is my testing environment
 http://imgur.com/yeSkKKD
each "001" folder contains the "!Read!" "Not yet Read!" and "Read" folder

I just want to know whether each time the score we get is the same
And here is the code :

click("1463106388340.png") #The head of 001 to get focus
t= "1463106289937.png" #The little pic of "!Read!"

a=0
while a != 30:

    print ("t")

    b=list(findAll(t))
    for c in range(len(b)):
        for d in range(c):
            if b[c].getScore()>b[d].getScore():
                b[c],b[d]=b[d],b[c] #just to sort result by score

    for c in range(len(b)):
        mouseMove(b[c]) #and show me by moving the mouse
        d=b[c].getScore()
        print d

    wait(0.5)
    a += 1
    type(Key.DOWN)
    wait(0.5)

The first 20 times is so smooth,
after 20times, each move (mouseMove or type) will delay for at least 10seconds.
Here is some Debug Log shows up:

[debug] KeyPress: extended delay: 10012
[debug] KeyRelease: extended delay: 10011

Can I use some other method to avoid this?
Or it must wait until the bug is fix?