The Log comment is not seen under activities when it is logged via Xflow -> Update status button. However when updated via command bar it is visible under activities.
USRD 17.3 RU3 / Windows
Release : 17.3
Component : XFLOW INTERFACE FOR SDM
This is a known defect and is currently under investigation by Engineering team with defect id - DE59816
Kindly raise a case with support to know the status of Defect.