Net::Whois::Raw versions before 2.99044 for Perl ship a pwhois command-line tool that queries WHOIS for the wrong domain for unicode domain names.
pwhois encodes each non-ASCII label directly using Net::IDN::Punycode and prepends xn--. Apart from lowercasing ASCII and Cyrillic letters, it skips the IDNA mapping and normalization steps, so a label with other uppercase letters, or not in NFC, encodes to a different A-label than its IDNA form. For example, a label of U+00C9 followed by "cole" encodes to "xn--cole-pka" rather than "xn--cole-9oa".
The Net::Whois::Raw library modules are not affected.
Apply the patch.
For deployments that cannot apply the patch, convert the domain name to its A-label form, for example with Net::IDN::Encode::domain_to_ascii, before passing it to pwhois. pwhois passes all-ASCII names through unchanged.