Inconsistencies in Quant vs Integrated Reasoning & CAT

Hi, I just wanted to find out the possible reasons behind a strange inconsistency in my actual GMAT test result - 640 (47Q/31V) with an 8 for Integrated Reasoning. In previous CAT testing I was getting 700-730 consistently. Furthermore, I was always getting a Quant score of 49+ (up to ~51) and Verba...