Assuming fungal activity ----- assuming only, maybe agri-fos treatment for a systematic treatment, or cleary's 3336. For non-systematic, could try mancozeb, or maybe a copper spray.
So strange, I think air movement is so important - I made sure to have it 2-3 feet from a window (I close the window at night to make sure the temp is ~65+).
I re-potted it in case the media was bad, the roots look terrific. What happened to you little guy?!
I worry a bit about antifungal treatments because I have a 3 year old. Their little hands get in every where... thank you so much for the treatment options, would any of those be considered "safe" if I sprayed the plant outside and then brought it in the house with kids paws around. I would move it out of her reach, but I do worry about things getting in the air.
Most welcome IP. Not sure about Cleary's 3336, but agri-fos, mancozeb, and copper aren't expected to cause issues with people in the concentrations used on orchids. Once sprayed onto the leaves and stems outside of the house, and then left to dry right out ------ it should be just fine to bring it back indoors later. And - if possible - put the orchid in a spot where a small child won't reach ----- if possible that is.
Some growers can still have their orchids do well in still air - depending on conditions ----- humidity etc. It's known that air-movement can help cut down on fungal activity on leaves. It just depends on circumstances. Eg. in a bathroom left humid and still-air for long enough periods of time, the mold can begin to grow on the walls, in between tiles etc ------ while airing and fast enough dry-out cuts down or prevents that kind of thing.
Anon Y mouse: thank you also, literally I was looking at the plant Thursday and it was fine, I woke up Monday morning and it was like photo. I wish it were away from the stem, I'd cut the area, but of course, right on it!
I did a little hit of H2O2 when repotting, then I rubbed some rubbing alcohol on it and put blobs of cinnamon on to keep it dry. It spread a tiny bit this morning, lets see... it will be an experiment I guess