This usually happens when the Leave Taken hours are more than the Entitlement Hours. The Entitled hours on the Leave Summary and liability report are the difference between the Entitlement hours and the Leave Taken hours from the employee's leave record. If the entitled hours are negative, the leave entitlement will appear in the Pre 93 line, and the pro-rata hours will appear on the Post 93 line item.
To avoid this issue, in Options, untick the checkbox Separate Pre and Post values when you run the Leave summary and liability report, and only one line for LSL hours for each employee will appear.