3827274 - Why can't I upload multiple receipts when claim an expense?

As per the requirements of users' company, they need to upload both receipts together with itineraries or other files as supporting documents for an expense entry, however, they found that they could only upload one image/file at a time when claim the expense at the first time. Only when they saved the expense and opened it up again, can they add more supporting documents afterwards. Why is that?

User needs to upload multiple images or files to an expense entry when claim it for the first time. , KBA , CON-EXP-ADM-MOP , Monitor Payees , Problem