time command sometimes shows garbage in "user" and "sys"

[Mayuresh <mayuresh%acm.org@localhost>]

I am on NetBSD 6.0 on i386.

Sometimes, and I don't know how to simulate this reliably, the time
command produces garbage (weird large numbers showing several minutes for
a 1 or 2s job) in "user" and "sys" fields while "real" time looks ok.

It is fairly frequent. I have a batch job where I measure timings in a
loop. Once in about 10 iterations the issues is bound to trigger.

Here is one example of the erroneous output:

real    0m0.196s
user    20m43.820s
sys     4m36.405s


Is there any other information I can gather and share to find the cause?

Mayuresh