I've been digging deeper and I've included %vs.id% and %header.host% in the access.log format to record the virtual server id and the host header.
The host header is recorded in Linux servers as "lvov1.ips:8173". I thought the port included in the host header was the issue. I went to another GF running on Windows but the recorder host value has the same format, so that was not the problem.
The virtual server id is always [b]server[/b] in the Linux box, but it changes in the Windows box depending on the url.
I hope the problem be a Linux configuration issue, but I haven't still found it.
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