2820976 - Amount field grayed out in APP Park Supplier Invoices for Enhanced limit item

You have a Purchase Order with an Enhanced limit item. If you simulate the creation of a Supplier Invoice via the APP 'Create Supplier Invoices' the amount field is open for input and you are able to add an amount directly. However if you use the webgui tile(s) 'Park Supplier Invoice (MIR7)' or 'Create Supplier Invoice - Advanced (MIRO)', the amount field not open for input, it is grayed out.

SAP S/4HANA Cloud

1) Create a Purchase Order for an Enhanced Limit item via APP 'Manage Purchase Orders' 
2) Call webgui tile 'Park Supplier Invoice (MIR7)' and create a Supplier Invoice with reference to the Purchase Order. 
3) The Amount Filed is grayed out. (See Illustration) 

"Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental."

Standard System Behaviour

In the Webgui based tiles, 'Park Supplier Invoice (MIR7)' or 'Create Supplier Invoice - Advanced (MIRO)' the amount for a limit item is entered in the item Account Assignment TAB

MIR7, Park Supplier Invoice, MIRO, Create Supplier Invoice - Advanced, Enhanced Limits, greyed out, input, grayed out , KBA , MM-FIO-IV , Fiori UI for Invoice Verification , MM-IV-LIV , Logistics Invoice Verification , How To