The controversy is basically about how the diaphragm works due to its shape. Some feel that it operates like an accordian and then both sides of the diaphragm would have the same action. The patents show a series of 'S' shaped pleats that expand and contract with the curved areas acting as surrounds. It looks like an AMT operates like a group of tweeters side by side. Therefore a dipole. I don't see how the diaphragm can work any other way.
As always, thank you for your help.