Leak Down

I decided to do a leakdown test in preparation for the upcoming season. 3 of the 4 cylinders had 0 loss at 90 PSI. However the 4th one was down 4 lbs. at 90 PSI with a noticeable hiss out of the exhaust pipe. The thing is the heads are basically brand new with 1 qualifying session an 1 race on them. Is it possible that the valves have not been run enough to seat/break in completely or do I have to get it fixed?



Thanks,

Garry