not a security related issue !
(1) gross mismatch between the 3270emulator setup and VTAM definitions
(2) procedural error... hitting the wrong key on the keyboard at the wrong time
aka known as PEBCAK
not much problem determination can be done from a forum
(1) network support
(2) somebody without fat fingers sitting at the workstation doing things the way they should
watching and telling the end user what he/she did wrong