I've had this orchid for several months now. It seems to be pretty healthy, it's grown a couple new leaves recently and has some new root growth. However, when I first got it, there was a little brown spot on one leaf. I didn't think anything really of it, maybe some slight damage to it, or just an odd coloration in the leaf or something. However, the spot has gradually seemed to decay, and a couple other spots on the edges of its leaves are showing similar patterns.

Should I be concerned? I thought it could be sunburn, but that would be pretty surprising, as it's near a north facing window with the blinds almost always closed. I have opened the blinds a couple times, but only because I thought that partial light that isn't filtered by the blinds couldn't possibly be enough for the poor thing.