From xFlow interface, when an analyst adds a watchlist for a ticket, we can't see this activity in the ticket activity log...what we can do to add the activity to ticket activity log?
Release : 17.3
This works as designed...that is, when an analyst adds a ticket to his/her watchlist, the ticket's activity log will not show this operation. However, the analyst can view the watchlist tickets easily from the left panel Watchlist stream/node.
The techdoc has this description about watchlist
Adding this operation to ticket activity log would need source code change and can be considered as product enhancement. You could submit an idea/enhancement request from community web site