Howeara lava burst, rot or something else?

[iSoup]

I have had this one for a couple of months now. I keep it by an east-facing window and water it by flushing it thoroughly once a week. It lost a smaller leaf or two since I brought it home, but I figured that could be from the shock of moving it from its cozy greenhouse. I’m in Michigan so it’s cool (low 60s at night and mid/high 60s during the day) and dry right now. I just noticed the bottom of its largest pseudobulb has become soft and brown. I can’t smell much if anything coming from it (maybe slightly musty).

What would you all advise? I am thinking of repotting it, removing the brown material, and maybe dosing it with some peroxide.