This is basically the education reform movement of the 90s and aughts getting their wish via the monkey-paw. Schools and teachers are measured and judged on how kids perform on standardized tests. Your kid is likely in the 95%+ percentile so there’s not much room for “growth” as far as the metrics are concerned. So their efforts are on pulling up kids from the 5th percentile up closer to the median.
Also, it’s not uncommon for low performing students parents to sometimes freak out at the school if their kid starts falling behind, so everyone scrambles to get these kids back on track so the parents don’t pull their kids from school (which will only make things worse for the kids academics)