Any modern fabric that relies on a PU coating to bead the water away from the fabric, will eventually let in moisture.
Water repellant coatings lose their effectiveness over time, and then the fabric soaks up the moisture, resulting in build up of condensation and dampness inside the garment, this becomes more of a problem in warmer weather.
The wearing of ruck sacs, and other items on your shoulders,will cause abrasion around the shoulders and waist, increasing the likely hood of moisture building up.
The only material ive tried that is virtually bulletproof, regarding keeping the damp out, in any weather, is Ventile.
I borrowed a relatives double Ventile jacket many years ago, and tried it out in the most hostile weather above llanthony.
The jacket does become quite heavy when saturated with rain, but due to the properties of the Egyptian cotton, it remains virtually dry,in even the heaviest of rain.
Few companies now manufacture walking clothing from the material, simply because it is incredibly expensive.
Your average jacket can cost over £500, and a double layered version even more.
Treated carefully,every top quality waterproof will keep the rain away, but due to their over all design, and reliance on water beading coatings, the moisture will eventually find its way through.