not a security related issue !
possible causes...
(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
![Very Happy :D](https://www.ibmmainframeforum.com/images/smilies/icon_e_biggrin.gif)
not much problem determination can be done from a forum
for ...
(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