There are no lists in scalar context! It's SCALAR context. What you have in 
  if (undef, undef) { # An extra set of parens doesn't matter.
      print "OK1\n";
  }

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is the comma operator in scalar context. Which evaluates its LHS, throws it away, then returns its RHS. Which is undef, and hence false.
According to the above
If with "above" you mean the post you're replying to, you notice I talk about list ASSIGNMENT. Not lists. Nor arrays.

In reply to Re^3: Can't understand function returning undefs by JavaFan
in thread Can't understand function returning undefs by rg0now

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