Oh I have seen this!
I had a lot of orchids (phals and oncidiums) affected with identical symptoms, and after some research I decided it was pseudo mites or false spider mites infestation. They are so small, you cant see them with your regular magnifying glass. They can be easily removed by water (shower) and they get dessicated when sprayed with rubbing alcohol (does not hurt the orchids). They can live on some orchids (Catts) without showing any symptoms, so if you treat only the affected plant, it can get re-infested easily by contact.
I treated ALL of my plants with spraying them frequently (every couple of days) with mixture if rubbing alcohol and few drops of soap. Alcohol will dry up any flowers or buds, so avoid contact. Then every 7 days I sprayed the entire plants pots and mix with soapy water and and then put them in the shower for 5 min. You will need to repeated this process 3-4 times to kill all of the mites that are hatching in 7 day cycles. Most of my plants recovered completely. The new leaves grew in healthy. I still shower them off occasionally just in case. With phals you just have to make sure to dry the top to prevent crown rot.
I hope this helps