I was personally (mildly) concerned about it because we've had two key figures thus far who faded away (Pestell and Patterson) and it wasn't a clean break. They just slowly stopped appearing or getting mentioned, ergo being dropped from a CC would fit the pattern.
So consider my fear about Dr. Rahman as PTSD from the last 3-4 years of being invested in Cytodyn.
The fact he's still on the website as CSO makes a departure seem highly unlikely, so yeah let's assume just a scheduling snafu.