It is possible the airdome, if present, could cause problems. I see people getting the biggest and baddest air pumps they can find. This is not DWC, you don't need or even likely want a lot of air. Even a small amount will saturate your medium. Too much air could cause all kinds of problems, root drying, etc. I've seen rootballs with a big hollow space in the middle where air got trapped. You don't want that. I've not been convinced of the worth of the airdome and don't use them, and I've grown some big plants..
Yikes another one? You should contact autopot and explain what is going on. They might know why this is happening. Might be related to the substrate around the airdomes? Or maybe it's not controllable and its random that you have to live with. But if you can get a tip from the company so it doesn't happen again that would be good.
Here is an email contact. Dan just emailed me 10 minutes ago actually. [email protected]