@Elezeid
Identified and fixed (sort of 😂)
Combo box with script swaps between factory and expansion content
Combo box saves in preset
Changing presets seems to re-trigger the combo box's value, even if it's the same as the previous preset, which initializes the expansion content and bumps the scroll window back to the top
Fix: Turn off "save in preset" for the combo box.
Voila! Bug gone. This is a slightly less than ideal way to browse content, as the user will have to manually swap content libraries via the combo box, but it is a small inconvenience when compared to the joy of browsing presets.
Hope this helps anyone else that runs into the issue in the future!