The newer caps with the vents like this - you need some air space for expansion to happen. You don't need the fluid all the way up to the bottom of the openings for the caps. You want at least 10% of the total reservoir volume for air space.
But yes, the vents toward the back is very important.
Wondering… It appears that Mopar discontinued the black caps in favor of the yellow ones. Are the yellow ones made of a stronger plastic, less prone to flex?
It makes no difference, it's just a color. They like to make safety critical items bright colors now. Most cars after a certain time in the 90s have to have transparent brake fluid reservoirs (plastic) with the max fill line clearly marked.
