Have a look at the last bill on the matter ledger, posted for June's period WIP.
Double-click on the bill on the ledger.
Select Billed Time tab.
Check the dates of WIP picked up, if there are any dates post-30th June, then WIP hasn't been correctly billed for July.
To Fix:
Double-click on the Credit entry which is paying the bill, click on the Payment Against tab, hover your mouse over the allocation row, right-click the mouse, and select Reverse Allocation.
Double-click on the now unpaid bill, select Edit Transaction (consider the period and date you wish to reverse the bill and post the one in – periods can be changed in Nominal Ledger – Transaction Periods), this bill is in the current month so there is no need to change the period, change the ‘Date’ of the reversal to the date of the original bill, and relevant Details, then select Reverse.
Raise a new bill picking up WIP to end of July 23 and Post.
When prompted, Allocate the credit back against the new posted bill.