Ordinarily, sendmail strips all the nonescaped quotation marks (those not prefixed with a backslash) from a key before looking it up. For example, the following key:

"Bob "bigboy" Roberts \(esq\)"@bob.com

will have its nonescaped quotation marks removed and end up looking like this:

Bob "bigboy" Roberts (esq)@bob.com

Note that all escaped characters are de-escaped (have the backslash removed) during this process.

When quotation marks and escaped characters need to be preserved in a key before it is looked up, you can use the -q switch with the K configuration command. The -q switch suppresses dequoting and de-escaping.