On Xbox, after downloading the new 1597 patch, hold the power button for 10 seconds to clear the console cache. Re-launch Skyrim to ensure the new scripts bake in correctly.
In November 2021, Bethesda released the Anniversary Edition upgrade, updating the game executable to version 1.6. This rendered the existing USSEP incompatible and caused a schism in the user base. Users relying on the Script Extender (SKSE) were forced to remain on the prior executable, version 1.5.97. Consequently, these users require a specific legacy version of USSEP that has been "backported" to function correctly with the older executable. skyrim se unofficial patch 1597 download new