I've seen something similar if the environment variable 'TZ' is set. This is consistent on both *nix and Windows:

F:\>perl -e "print scalar localtime"
Thu Sep  9 08:18:24 2004
F:\>set TZ=MST
 
F:\>perl -e "print scalar localtime"
Thu Sep  9 14:19:25 2004
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And on *nix:

$perl -e "print scalar localtime"
Thu Sep  9 08:20:26 2004

$export TZ=mst
 
$perl -e "print scalar localtime"
Thu Sep  9 14:20:35 2004
[download]