Discoloration of Onc. Pseudobulb...Is it Rot?

[Ingrid76]

Please take a look at the discoloration of this pseudobuld. The tag reads Wils. Red stars ‘Rooster’ which I received as a gift, so I’ve had it now for about 3months. All my orchids are inside due to the unusually cold winter here in Florida. I keep the ceiling fan running on medium and try to keep the humidity around 53. I recently added a Wonderlight 160w for more light for the Onc. and Catts. to far from the window.

Here’s my question, is this some type of rot? It’s not soft to the touch and the rest of the plant is not showing signs it’s in trouble; however, this spot is growing. What should I do? All suggestions are welcomed.