"On Mac, when I profile something and use Running Time as a sorting column, only the root nodes get sorted.
Expanding a node does not give children sorted by the selected sorting model."
This is due to how we do the storage/sorting of the call tree view, so indeed a bug.
Fixed in version 0.30.0.74 (master)
Author: Rodrigo Moya
Commit: e23c4a7229f850c519c3fd74fb12eecbc19ab198 (xamarin/profiler)
I have checked this issue with latest profiler build i.e. profiler-mac-0.30.0-108 and observed that this issue has been fixed. Here is the screencast for the same.