I don't grow that one, but I do grow ones similar. First, get it out of straight perlite and put it in a mix of fine orchid bark and perlite (50/50 ratio). Before potting it, check the roots and the stem the roots are growing out of. The roots should be white, green, or yellow (heck, my multiflora has orange roots..totally normal), intact, and not appear to be shedding or stringy. The stem should not be yellowing or brown/black or mushy. If any of this is happening, re-start the rooting process.

If this is anything similar in care to my wayetii, it can tolerate a bit of drought. I would water it, once well-rooted, once every week or two, depending on how dry the medium gets.

Was it the top or bottom leaves that were lost?

It lost two of its newest leaves. Thanks for the advice, think I caught it in time. I used to root in straight perlite but just forgot to repot it, I have it in a mix like you described now. The roots were dense, fat, and white. Almost certainly a media issue, appreciate the watering tips. Will keep an eye on it, what is there looks good and healthy.

If it was the top two leaves, they probably just got bumped or bruised and didn't recover. It happens. Bottom leaves yellowing is my first cue to check roots and root stem for rot.

Sorry, yes it was the top leaves. But that is really good to know.