New comments do not display in Ticket Conversation widget on the Ticket Form page
This issue can be caused because the Ticket Conversation widget is tied in with the Activity Formatter on the form in the platform UI. The widget looks at the Activity formatter on the form and also the presence of the Journal fields on the Activity Stream. If those fields are not added or the Activities formatter is not added to the form, the comments being added are not shown on the Ticket Conversation widget on the portal.
In order to resolve the issue, navigate to the target record for the ticket on the platform UI and make sure the Activities(filtered) formatter has been added to the form layout. Also, make sure the Journal fields are present in the Activities filter.