Little-Bee, I am sorry your question has not been answered, I am not good with dens so I was hoping someone else with experience would answer. Remember that even though direct sun does not touch an orchid it can still develope heat blisters.that being said I am wondering if your den picked up a fungal issue from the tree it is attached to.being outside it is more open to bacterial or fungal problems.do you use fungicides?If not you could try to spray it with some phyton 27, it is an all in one spray.now I ÷now they say it should not be used on dens but I personally use it on mine with no ill effect.i do hope it will get better and someone else will chime in.good luck VelletaðÂÂÂ.

Orchids get all sorts of spots, some from mechanical damage (sun, bumps, etc. Nothing about your plant would concern me. Could be water, sun, a bit of fungus but I wouldn't change anything or treat anything.
Many plants are full of brown spots and they grow and flower.

Jane