Promenaea in need...

[TreeBear]

Hey, I was wondering if you guys would be able to help me out?.. I've been growing a Promenaea 'Chameleon' and have had it for a few months without much issue and it seems to be going a little bit south now..I had gone on vacation and it didn't get water for 2 weeks When I returned it surprisingly wasn't going too bad, but then it started getting some brown spots, leaves turning yellow and beginning to fall off. I'm not sure whats going on with it, as now that I'm back, it has ample attention and moisture.
for some background: I've been growing it among my others, in a glass display case. I use T5's for lighting in there and also have 2 fans for air movement. Temps stay from approx 70-80°F (night and day).
I'm sad about this one. If any other background is needed to determine plz let me know. I can't think of much else..all my others are doing just fine.

I once heard something about Proms being deciduous, is that true or is that malarkey??Does it have some sort of fungi, rot, or disease issue?
please help if you can, I don't want my pretty lady to die.

[WhiteRabbit]

[IcePenguin]

I have a promenaea which I've had several years. My understanding is they do not like being repotted and you have to pick the right time if you repot. I also never let mine dry out, I water before it totally drys out. As for light, this one sits in a north facing bay window, no supplemental lighting. It grows quickly for me me, blooms a few times a year. The leaves do get some spotting, but it doesn't seem to be an issue. I find it a fairly easy plant to grow. I call it managed neglect.