Yellowiing leaves: age or worse?

[berthabloom]

I have what I call a Cattleya, mostly because it's a NoID, but I don't really think it is. It normallly flowers in Sept. Last Fall, 3 nice sheaths formed, then turned brown around Nov. and I thought they were goners. I decided to repot in Jan, cut open the sheath's to investigate and two weeks later I had lots of blooms. Since then I had one leaf yellowing. No worries. Today, there seem to be a bunch more also turning yellow. They are not the oldest psuedobulbs, so I'm now concerned.
I'm in Fl and this plant is outdoors. Bright east,morning light, no direct sun. Water every 3rd day or so as potted in bark/charcoal/clay balls mixture. Using Peters 15-5-15 very dilute twice a week right now. The max temp has just hit the 80's in the last few days. No sign of insects.
Do I have a bigger problem than old age on the yellowing leaves? I've had this plant for years and haven't had any issues until now.

[Dollythehun]

I'm guessing, so I want to hear what others say. But those are beautiful flowers and to my "novice" eye, it looks well grown. I have one that regularly looses old leaves but, never new.

[Roberta]

In the last photo, the pseudobulb attached to the yellowing leaf also looks like it is on its way out. The older p-bulbs do that, tend to drop leaves first. As long as the new growth looks good, I suspect that this is just "force of nature". Blooming from dead-looking sheaths is characteristic of some Catt species, that are likely in the background of your plant, (C. aurantiaca comes to mind, often a source of orange or yellow, combined with other things to get the nicer flower form) Blooming more than once in a year is also likely to be the result of the cross of, perhaps, a spring bloomer and a fall bloomer.