Symptoms

Processed expense line from a project task doesn't roll up the state of expense line on the project and because of this Actual cost doesn't rollup from project task to project

Cause

OOTB scheduled job "Process Expense Allocation" was deactivated which is responsible to update the expense line state from "Pending" to "Processed"

Resolution

The update of expense lines from state 'pending' to processed' on project form will occur automatically via a scheduled script which runs daily 
scheduled script: https://<instance-name>/nav_to.do?uri=sysauto_script.do?sys_id=11ed14619f312100d7f5f79ff57fcf09 

This field is updated once the Expense Allocator runs the allocation rules (line "new ExpenseAllocator(gr).processRules();" in the auto script). Once the expense line on project form shows as processed it also rollup the actual cost from project task to project level (Make sure sys property ‘com.snc.project.rollup.cost’  should be true)

After activating the scheduled job "Process Expense Allocation" the issue should be solved.