I have definitely had that issue, and I always attribute it to "wrap irritation". At 7 weeks you're still doing a lot of healing. I actually have a very reactive stomach and get gastritis quite often. When my stomach is irritated, my wrap can feel what I describe as irritated (after all, my wrap is created out of that same reactive stomach) when it's empty--particularly in the morning. As soon as I eat breakfast it feels fine again.
If you don't have a generally reactive stomach, and don't get gastris easily, I'd attribute your experience to being at an early stage of wrap healing. I truly don't think it's something that will continue once complete healing has occured.
Hang in there...this too, will pass!