I did a quick search for studies for the effect on CBD on Executive Function. One research basically found that *synthetic cannabis or CBD had harmful effeffects on EF.
I also found this: https://documentcloud.adobe.com/link/track?uri=urn%3Aaaid%3Ascds%3AUS%3A7d4213fd-d00e-4aed-acbc-e370ebaaf8ba
which should be a pdf that takes about improvements on executive function with CBD oil. Some of it may be due to better sleep, for example.
Anyway, I would love to see any links or references to the negative research mentioned above.