varnish serving a wrong file

[Zhiping Deng]

Hi,

I have been using varnish for about 2years.
Recently I discovered that sometimes it served a wrong file.
for example:

The url is /foo/a.jpg, but the response content is actually from
another file (/foo/b.jpg)

I upgrade to varnish-3.0.2, and it still happens sometimes.

What's the possible reasons of this problem?

Thanks,

Zhiping Deng