Could air filling the ostomy bag be a sign that the bag is too tight?

Hello everyone, my fiancé has an ostomy, due to just having a tumor removed in his stomach from cancer. I changed his two piece, ostomy bag yesterday, and thought that it might be too tight. He feels like it's okay. This morning it was filled with air. Now although I know the bag filling with air can be a natural thing, I was still wondering if the bag could be filling with air due to the circle being too snug or tight? This was my first time helping him change since he's been released from the hospital 5 day's ago and I am still trying to get comfortable with assisting him. The first measurement we tried was definitely too big, we could still see the skin, but the second measurement he chose was, in my opinion, a little too snug. So I worried all night. Then he woke up telling me his bag was filled with air. So of course he went to the bathroom to empty the air, which I think is a natural gas situation, However, as I stated before, he hadn't had this amount of air in the bag until now; after I changed his bag.

mine always filled up like a blimp overnight to the point there was absolutely no more room for air in the bag

Mine always filled with air while I was sleeping too. I am surprised it didn't pop off. There's no good way to get the air out of the bag. The filters don't work, and even if they did, with an ileo, the output tends to be thin enough that it covers whatever function the filter had - if any. I've never noticed the filter being very effective. People sometimes "burp" the bag, but I think the best thing to do is to empty when it's like that. It was one of the things I disliked about the bag, the air. It was probably the thing I disliked the most... That and involuntary sounds. People say over time, the gas calms, but some of us had temps and never got to that point.

There's a product that's like a little window you can install.
/www.amazon.com/KEM-Osto-vent-Osto-EZ-Vent/dp/B000M8FR4E
I tried it when I had my temp. I remember I installed these on like 10 bags at once one day. it was fun to try, but it didn't work well for me. Whenever I opened the little window, it would just get output in the hole and I'd have to swap the pouch for a new one. Some people love it though.