Black rot on leaves?

[bogdan]

These orchids really keep us on our toes, don't they?

I have this C. lueddemanniana since last year and it grew a wonderful pseudobulb and now is working on growing a new one (which is fine, for now). In the past days I observed some purple markings on the back of the leaves, that now are spreading to the front as well. No soft spots, the leaves look normal except for these spots. It is growing in Vanda light, the kind that makes them almost bleach.
What is your opinion, should I take the scissors out of the drawer?

Thank you