I have to return to the office to get a better look at the images you provided.
Vertical PEX piping requires additional supports. **When/if running vertically, PEX should be supported every 4 to 6 feet.
I see rust and floor satins due to bulk water.
Pinhole leaks are notoriously hard to identify, but here are some clues for their existence:
Mold or mildew growth.
In the world of plumbing, pinhole leaks are silent assassins. Pinhole leaks are also exclusive to copper piping.
We do not always feel bulk water or spray. The mineral build-up is one clue. The thick green patenia at the fitting and visual whitish streaking to the left are suspect indications water has leaked down the TPRV tube.