Topcashback USA used to work great for me. Now it never tracks IHG properly.

I've switched over to the AA shopping portal, where my clicks do seem to be tracked but I have yet to receive miles (or even confirmed stays) weeks after check-out.

I do have "tracked stays" that were cancelled long ago, so clearly IHG is far worse than other merchants / travel companies with affiliate marketing... It's a shame, because their cashback rates are usually the highest - and being more reliable would be quite the competitive advantage.