This little program works fine to convert a UTF-16 file to UTF-8:

#! perl use encoding "utf16", STDOUT => "utf8"; while (<>) { print }
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But when I try to do what I think is the same thing from the command line:
perl -Mencoding=utf16,STDOUT,utf8 -p -e 1 < in > out
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The resulting file is a whacked semi-utf-16 format.