I would recommend checking the roots in the potting medium as well. I have found that bark mixtures don't stay moist enough for some phals...I have one of these and it is in a sphagnum moss/bark/perlite mixture. I let them dry out in between watering due to the moss...with sphagnum moss it is easy for me to rot roots...but this one seems happy as a bug in it. Check the roots and let us know what the prognosis is! Something has got to be dehydrating the leaves!

I have it in a clear pot and it has tons of healthy roots. The only thing I notice is that there is some green moss growing in the pot. Is that bad? No bugs or anything.

The root tips are green... I really am baffled.

Clear pots are the way to go. Sounds like the roots are still good in the potting medium if you can see them. Maybe like others mentioned, it is just exhausted from blooming?

when was this repotted? is it green moss or green algae that you see?
Re: leaves - in some of your photos, looks like there's only one (maybe two) sets of leaves. Have leaves dropped? From the base of the stem (main plant) or near the crown?
This is a puzzler ...

It was repotted in march of last year. I don't know if it is moss or algae. I could be algae. It is growing on the inside of the pot on the sides. I have lost two leaves this past year. One of the newest leaves got some sunburn last summer when I took the plant outside to water and forgot it out there... OOPS. If you look at it closely you'll see that the second or third leaf is cut in half. that's the one that burned. This was months ago and it has flowered and put out two new leaves since.

I use clear pots for some of my phals and even though the roots look good through the clear plastic, I repot them every year after flowering.

The new set of leaves is a good sign but I would still repot the plant now.

PS ... algae on the roots can be harmful, especially if it's so thick that the roots suffocate.