Water comes up clear.

When I first got my Bialetti Mukka, it would leak from the sides.  Online, I found the fix of soaking the O-ring in hot water before using.  I was using Peets ground coffee and it worked fine for months.
Now, I switched coffees (one fine grind Nero, one medium ground Fresh n Easy), and water comes out clear.  However, if I turn it off for a while when water first steams through, then turn it back on, it comes out with coffee.  Anyone have this problem or know a fix?  I've tried tampering with temperature, high, low, still same problem.
Thanks!