Check out the following Technical Article to see if this helps you
The Investment Status Lookup is not showing all active values
Document ID: TEC439273
A project, with a simple budget, can only be changed to 'On Hold' if it has a Progress of 'Started' and the current date falls between the Budgeted Cost Start date and the Budgeted Cost Finish date. Status of "On Hold" is not available unless the project status is approved. You will need to change the status to "Approved" prior to selecting "On Hold".
Therefore, I think you might need to check your Financial Planning Date Ranges. Check to ensure the current date falls within the date range of the plan.