Your problem has been identified, and a number of other issues have been pointed out. This one hasn't been mentioned, but caught my eye:

unless ($found == undef) { ...
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That's not doing what you probably think it is. undef in a numeric context like that is 0. So, if $found is... wait, where is $found being set? Actually, I have no idea what is happening there.

The point was that you should test definedness with defined():

if ( defined( $found )) {...}
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Thanks to a series of coersions, your code is functionally equivalent to:

if ( $found ) { ... }
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