$F1hash{$ptfkey, $ptfpn} = $ptfpn;

This looks very fishy to me. Are you sure you want to use this as the hash key? The key will be a concatenation of complete line (including the newline), the value of $; (defaults to "\x{1C}"), and then the line again, but with trailing and leading whitespace removed.

I think you just want $F1hash{$ptfpn} = 1; here.