Beallara dropping leaves

[snappyguy]

I acquired a Beallara Pacific Treasures 'Everything Nice' in late October. (Bllra = Brassia x Cochlioda x Miltonia x Odontoglossum) It is a member of the Oncidium Alliance. Since it's been in my possession it has lost 2 leaves off of the largest pseudobulb, and the leaf on the second pseudobulb is yellowing. It has also started growing a 3rd PB off of the largest one. I have checked the roots and there are no signs of rot. I use a bamboo skewer to check that it is moist and water when it dries, roughly every 7-10 days. Humidity might be a bit low. It varies between 40-70%. Temperature varies from about 63 at night to 70 during the day. Any ideas as to what could be causing the leaf drop and yellowing?



Thanks,
Mark