I just played my Durga 3 alto last night, had the stock ligature in the middle position. A Vandoren 2.5 squeaked viciously, followed by a Rico Royal 2 (better but still squeaking).
Kylo, please forgive the late response. I found that moving the ligature up to the window solved the squeak with my Durga alto with the Rico Royal 2. Have you tried shifting the stock ligature position on the mouthpiece? I play a Durga 10 with a Vandoren ZZ2.5 on my Yanagisawa T991b with few if any squeaks, again with the ligature placed closest to the mouthpiece window. Going to the 2 solves the squeaking, but I prefer the sound with the harder reed. I wonder if squeaking worsens with the ligature pulled back because of the reed not being held tightly to the table.I have the same problem with the TW durga on my tenor. It's sound so good but the squeaks are annoying.. :/ i have to try any others ligatures on this excellent mouthpiece with a unsuccessful stock ligature.