Oncidium Dancing Lady Die Off

[lespaul64]

Have an Oncidium Dancing Lady that's been blooming for me for at least two years off and on. Noticed some black root and rot while it was recently in bloom and decided it was best to risk repotting. I've generally never repotted a plant in bloom as I've heard it's not the best idea. I trimmed off all of the dead roots and any black root. Within 5 days of repotting the plant looks terrible. The bulbs have shriveled ed and the leaves look almost like they are dark at the base (almost "wet" looking) and they are all rapidly falling off. Curious if opinion is disease or just shock from repotting. Pictures of Fallen off leaves attached. Notice the marked dark area near the base.

Thx!
Ken