In my experience, X-T2 with grip, using Wasabi cells in the grip and original NP-126s in the camera, typical to get > 1000-1400 shots in this configuration writing to both slots, if shooting only jpg then you will get more. EVF/LCD auto switch, 1 min sleep setting. Use boost sparingly when it really counts. Sounds like you either have a hardware issue OR something going on with your batteries. Have Fuji inspect.