Yellowiing leaves: age or worse?

[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.