When creating a goal for a client, it is important to setup span dates for that goal. If there are no span dates, then the goal won't disappear during a new span.
Go to the 'Client Information' tab and open the 'Span Date' section. The image below will appear. Enter in the new span dates and any other appropriate field and select 'Add Span' at the bottom of the section.
In the notes field, it is recommended to put 'Goals' to differentiate this span date from other span dates that could be entered for the individual. Maybe something like "Used for Goals".
Also, make sure to refresh the page after save the new span dates before moving on to the goals section.