Unclear about Schoenorchis gemmata light requirements

[JFeathersmith]

I bought this little plant about 13 months ago at a show, after being smitten by a blooming specimen on display. I talked to the vendor about light and water requirements, so it's been living in my bathroom since then, since it sounded like the low light in there would suit it.

The room has 1 east-facing window that has a coating on it that prevents seeing through the window; it does get very bright in there, but I've had the plant several feet away from the window. It started growing a new leaf in early December, but it's been so slow, and our winters are so dim, that I've been concerned maybe it isn't getting enough light. I was watering about once a week until this winter when I started watering more often and fertilizing it every other watering or so, to help it with the new leaf.

Then several weeks ago, I put it nearer the window, maybe 6 inches away. We were having a long stretch of unseasonably sunny weather, so it was REALLY BRIGHT. After a week or two, it developed dark coloration along the edges of one leaf and the tip of another. I know for some plants, this means "too much light!" and for others it means "this is great!" but I've been unable to figure out what it means for this species, and as often as I've read what its light requirements are, I don't have a good handle on translating that to my conditions OR how to interpret what the plant did in the brighter light.

I posted about this on another forum, and someone wondered if maybe the plant had cold damage - it is colder close to the window, and our nights are still in the 40s (tho the apartment doesn't drop below 65), so I thought perhaps that was possible, but after putting the plant back on the wall, away from the window, the dark coloring has faded.

Which is great! It hasn't been sunburned, or cold damaged. But was it happy with all that light or no? Almost all images I've seen online show solid green foliage, so I'm assuming the dark coloring is a sign of too much light, but perhaps not a dire sign of stress either.

I think it's not getting something that it needs, because the leaf it finished growing before this one is shorter than its earlier ones. :\