My Den Laevifolium in trouble ?

[gngrhill]

I got my Laevifolium in bloom in spring. The flowers have since faded leaving some bare PBs and some with leaves. Now one by one the leaves have turned yellow and fallen off. I have read that the are NOT deciduous, so what do you think is happening ? It is in SMoss, which I keep just damp, in a bright location, no sun. Temps 85 to 90 F days and 60 to 70 nights, 50% humidity. fert. every other week.