From the docs for perlre

NOTE: Failed matches in Perl do not reset the match variables . . .

You can see this more clearly with a slightly modified version of your code where the leading characters are 'xxx' instead of 'zzz'.

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

foreach my $name (@files)
  {
    my $match="no ";
    $match="yes" if ( $name =~ /(^[a-z]{3})\.(\d{2,3})\..*\.ccc/) ;
    print "$match, $name, match1: $1, match2: $2\n";
  }
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The variables $1 and $2 retain the values they had on the previous successful match.

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