Solution : https://service.sap.com/sap/support/notes/410189 (SAP Service marketplace login required)
Key words :
se38-> utilities -> settings -> editor -> back-end editor open, frontend editor generates undefined characters, back end version, percentage sign reason, sapgui version > 46d, lf_for_destination_sapgui function module, complete correction instructions, correction instructions, modification assistant, ebcdic code
Related Notes :
| 437480 | Sending control characters from AS/400 to SAP GUI |