($out,$err) = $ssh->capture2("{stdin_data =>yes},cfgsave");
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This is not what you have been told by Myrddin Wyllt in an answer to your previous question about the very same problem. Try:

($out,$err) = $ssh->capture2({stdin_data => 'yes'}, "cfgsave");
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Note that ({foo => 'bar'}, "baz") is not the same as ("{foo => bar}, baz"):
The first expression is a list containing an anonymous hash and a string. The second is a list containing a string.

update: added missing '}'