First, the updated norms:
2025 NWEA MAP norms update, with data from 2022-2024. This is the mass of data, with practically everything you could possibly want to know--but you might have to dig for it:
https://www.nwea.org/resource-center/white-paper/88182/MAP-Growth-Norms_NWEA_Technical-Manual.pdf/Quick reference/cut sheet:
https://www.nwea.org/resource-cente...norms-quick-reference_NWEA_onesheet.pdf/Secondly, to your specific question: it is possible that this is reflects the updated norms. It is possible that it reflects the reduction in support. It is also possible that it simply reflects standard error and/or regression to the mean, and his ordinal position in the right-most tail of the norms, where a very tiny change in raw score can result in a relatively large change in percentile. I would suspect, based on the absence of significant test accommodations for most high-cognitive EF-weak learners, that this is not a reflection of lower support, since his test conditions probably did not change, and the material on the test is very likely below his level of optimal instruction (hence less affected by his instructional environment).
Thirdly, to your not-a-question-more-like-a-comment: that, sadly, is a common aggravation encountered by many learners with EF challenges, gifted or not gifted. So sorry to hear this.

And finally, did they move your DC to a 504 accommodation plan for ADHD? Even if he no longer demonstrates a need for specialized instruction, specialized accommodations are a separate question. The disability is still present and probably still acknowledged. If you can get a 504 in place, one of the options we've used in our building is essential assignments only, with EF-forward or repetitious skills reinforcement tasks excused.