2012 Tacoma V6 What causes a flapping noise when A/C recirculate air is on?

What is your question?

The flapping noise is behind the glove box and only comes on when A/C recirculate air button has been activated.

What makes this problem better or worse?

Only sounds when recirculate air button has been pushed

How long has your 2012 Toyota Tacoma had this problem?

Several weeks