Pseudobulb rot in Pot. Congaree Mendenhall?

[Chunky_Punk]

I hoping some of you can help with this issue, one of the latest showcasing my inexperience.

I purchased this plant, identified as Pot. Congaree Mendenhall and it appeared to be in good shape. Last week I noticed what appeared to be a discolored blotch on one of the pseudobulbs that I'm fairly certain wasn't there when I bought the plant. I kept an eye on it for a day or so, began to panic when I convinced myself the blotch felt squishier than the surrounding healthy looking portions of the bulb and the other bulbs.

Paranoid, I pulled the plant out of the pot and found nearly all the roots were dessicated. Why I'm not sure. I don't believe I overwatered. At the time I pulled the plant the roots and medium were bone dry, but I realize they could have died from overwatering at some earlier point and just dried out...

Ultimately, I panicked and cut off the suspect pseudobulb. I then cut into it to examine the splotch and discovered that it didn't appear, to me at least, to have existed in the bulb at any real depth. Almost seemed cosmetic, if that makes sense. I will try to include pics in the post below which will be my 5th...Thanks very much for any thoughts on this. Did I do the right thing or overreact, and how far does this set my plant back?