This year I moved my Aeridis into my new setup under grow lights and away from my cooler window. Its had these weird markings on it for a while and they're slowly expanding. I can't figure out what they are and have been slowly growing in size over perhaps 4 months? They're not a different texture to the rest of the leaf (which worries me that its a systemic issue). It also hasn't flowered this year, and growth is slow.
hey LR,
it look like cold stress. You were clearly thinking it was already being kept too cool so that's probably what it is.
It can cause stress for months to follow.
cut off the affected area just to be sure it's not something that can spread and keep an eye on it.
I don't think it's anything too serious the plant won't grow out of.
To me, the appearance makes me think past damage (I suspect mechanical, but may have been due to an insect or pathogen), followed by a secondary infection.
I believe a copper-based treatment may be in order.