If there is no match the content of the capture variables is bogus. The fact that their content is a different value of bogus between different versions of Perl is not so important as the fact that the value is not defined when there is no match. Your code would be better written:

use strict;
use warnings;

my @files = ("zzz.21.yy.ccc", "zzz.220.ccc");

foreach my $name (@files) {
    chomp $name;
    
    if ($name =~ /(^[a-z]{3})\.(\d{2,3})\..*\.ccc/) {
        print "yes, $name, match1: $1, match2: $2\n";
    } else {
        print "no, $name\n";
    }
}
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Prints:

yes, zzz.21.yy.ccc, match1: zzz, match2: 21
no, zzz.220.ccc
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