The following works for me:

my $input1 ="<span color=\"#231f20\" textOverprint=\"false\">%PN1%</sp
+an>";
my $input2 ="<span color=\"#231f20\" textOverprint=\"false\">%DIMMM%%D
+IMINCH%</span>";

my @matches = $input1 =~ m/%([^%]+)%/g ;
print @matches,"\n";

@matches = $input2 =~ m/%([^%]+)%/g ;
print @matches[0],"___",@matches[1],"\n";
[download]

HTH, Rata