Good morning Xi;

I had the same thing happen to a number of phals. I had to move them
off the shadded patio (SW facing here in SE Florida) due to painting of
the outside of the house. They got sun a few hours a day and I noticed
spots on some of the leaves. Assuming "sunburn" I moved them into the
shade.
Please permit me to thank you for posting the quesion and thanks to
those who answered.My mind is now at ease. The humidty here is great
for orchids. (wish I was an orchid)
Bob