I had this happen as well, can you give some more information about your usage scenario (what tool, size backing plate, pads, speed settings, your technique, etc). I think all these things play a factor.
In my case this was happening to me using the 'full' sized Griots Garage DA, with the 3" backing plate and pads. It turned out to be a few things for me, but ultimately I think it was that I was using techniques taught for a 5-6" pad with a smaller pad.
1) I was using too much pressure (probably even for a full sized pad- but the work of course is concentrated with a smaller pad), and too many section passes 6-8
2) I was using speed setting 5, and was advised not to go higher than 4 for the smaller pads.
After adjusting my technique, I now do about 4-5 section passes, speed setting 4 and using a lot less pressure than I was. Results are coming out great, and have not had a single issue yet (before that I had ruined about 4 or 5 pads in only a few days...).
I never had any issues with the 6" pads, even when I was using too much pressure, so may be a different issue in your case, but that is definitely what I saw- the backing material melting and ripping away from the pad.