My sim has the responsible trait, so when they go to work they work hard. Everyday they return with the mental fog buff. I have taken vacation, exercised, had the moodlet go away and the next day it is back. Playing on PS5.
Edit By Crinrict: Adjusted Title fit migrated bug report: [OPEN] [GRO] Mental Fog After one Day of Hard Work | EA Forums - 11598111
The migrated bug report had around 33 me toos at time of closing.