random() weirdness

[Igor Schein <igor@txc.com>]

Hi,

? ?random
random({N=2^31}): random integer between 0 and N-1.

? setrand(1);random
1000288896
? setrand(1);random(2^31)
1559883374

How can that be?  Is help lying?

Thanks

Igor

P.S. 

I remember there was a discussion once whether or not a better RNG
should be used in pari.  The argument against was that the current one
is good enough for internal functions.  However, users would really
appreciate something like Mersenne Twister implemented in pari for
direct use.