Uncooked oats doesnt agree with me either.
The high gi vs low gi thing is very overrated.
For starters, it's irrelevant when you begin to combine foods together. Which I believe is the case for you as I dont think you are eating a meal of just rice or just oatmeal.
I replaced oats with kool aid and felt much better for it. On a cut, satiety becomes an issue, kool aid isnt good for that.