Now, I don’t know if this bug may be related to using a mod body (1978 Future bound AKA de lorean) or if it affects all bodies, but it somehow manages to have more cargo space with 2+2 seats than with just 2 seats. That seems a bit irrational. Seats if anything should eat into cargo space and not create it.
So, more seats makes it bigger on the inside?
Now that I think about it, maybe it goes along this logic:
Add +2 seats > front seats have to use less space > +2 seats are foldable > cargo area is smaller, but can be enlarged with folded down back seats
And while this makes some logical sense from one step to the other, overall it’s still quite wacky.
Not all bodies are affected by this bug; the Z16A GTO body set, for example, doesn’t suffer from this problem, as I recently found out.