You know, there might be quite a lot in this. If the “fat-adaptation” ideas are right, in that your body becomes accustomed to utilizing fats for fuel rather than glucose, there might be a lag period when you load up on carbs. Since your body is still utilizing stored or consumed fats, it “ignores” the carbs in your meal and your BG rises beyond what your basal+bolus would normally handle (because your liver and muscles aren’t taking in glucose to form glycogen at all).
I think you’re on to something! The other thing I’ve heard is that “eating low-carb raises insulin resistance.” I’m not sure that theory makes more sense than yours.