Perl is deduced because of the detection of mod_perl and Wappalyzer is displaying the version number for mod_perl so it is an expected behavior.
Perl should be detected via the headers too:
"Perl": {
"cats": [
27
],
"headers": {
"Server": "\bPerl\b(?: ?/?v?([\\d.]+))?\\;version:\\1"
},
"icon": "Perl.png",
"website": "http://perl.org"
},
Most helpful comment
Perl should be detected via the headers too: