Rivals - "Where Dreams Are Driven" - "Reset to stock tune" button does not allow to enter the event

Self explanatory. Upon entering this event with a stock Honda NSX-R with only tuning applied, the player is given a prompt to “Return to stock tune”. When pressed, it does nothing. I still cannot enter race in the event because the car is somehow still tuned. When I returned to the garage, I saw that the only tunable values, that is tire pressure, were stock. After leaving the garage with nothing changed, I was now allowed to enter the event. But why should I have to return to the garage in the first place?