It is possible this is normal leaf loss, but then again, these leaves look just a little odd to me. It is difficult to say just looking at these pictures. You might want to read my comments on looking for mites in this thread.
http://www.orchidgeeks.com/forum/gen...=mites+reddish
You may also want to read this if you have not found it already.
Skewer use for watering of orchids