Pex Manifold and couplings leaking

[AzWldctFan]

I live in Chandler, Az with very hot summers. My house is 6.5 years old and in the past 6 months I've had two very slow leaks cause ceiling damage. In both cases, it seems like there is hard water sediment on a hot water Pex line near a manifold. I had a few plumbers comment on the color of the couplings looking yellowish/tan/beige instead of the usual white. I've also been told if these couplings sat in the sun before going in my house, they would have taken on UV damage and it would explain the discoloration and why they are failing.

Would it be normal for these couplings to get discolored and break down just sitting in the hot Attic, or is it most likely they were installed with that color? I have tons of these in my house and feel I'm just playing a game of whack-a-mole waiting for the next leak to sprout up.

Link to pictures of the leaking parts:
https://photos.app.goo.gl/NmPT8dkojoTGSFZ86

Thanks y'all!

 

[frodo]

looks to me the pex pipe is not shoved up onto the barb fitting all the way
but, that could be just me looking at a picture.

i am curious what the actual temp is in an attic in Arizona,
and the max temp the rings can withstand,