Milestone message when changing the End Date on tsp1_project_task table.
This is message is coming from the "Sync duration and milestone on update" Business Rule.
It appears that this is happening due to the "Planned duration" field not existing on the form (duration).
Because of this, the related Client Scripts are not able to change the Planned Duration value when the End Date is changed. The system thinks that it has 0 duration and it becomes a milestone.
You can easily fix this by adding back the needed "Planned duration" field.
To do this, follow the steps below.
1. Navigate to "tsp1_project_task.LIST"
2. Open any record
3. Right-Click the Form Header and go to Configure > Form Layout
4. Move the field called "Planned duration" from the Available list to the Selected list.