dying leaves on Paph. Wössner Kolarmi

[lobotomizedgoat]

This little thing looked pristine when I picked it up mid October. By mid to late November the first and then second lowest leaves started yellowing. The first photo is from 12/6 and the other was this evening 12/9.

I'm wondering if this is natural senescence or if there might be an underlying problem.

Brown leaf is dry and not slimy. Temp has been 65-75 F, RH 55-75%, watering has been every 5-8 days depending on how dry it seemed (7 avg), gentle air flow from ceiling fan. I have larger paphs in the same media and pots (3.25" wide, 3.75" tall) that definitely dry quicker. This one is a bit wobbly so I suspect the roots don't go very far.