Call transfers involving DAHDI extensions not working

I just found that call transfers between SIP extensions are working, however, if one leg involves a DAHDI extension, bizarre things happen.

Here is an example that just happened to me, and I repeated it to verify.

  1. A call comes in and is answered at a DAHDI extension.
  2. Press *2, enter extension to transfer to.
  3. Hang up after the they answer.
  4. Now, both legs hear music, they cannot talk with each other. If they hang up, 30 seconds later they get ringback with music when they pickup.

I have to go to FOP and manually kill the call.

Oh, to make it more interesting, I see that BLIND TRXF works fine. It is just attended transfers that have this problem.