I did some google searches for this and didn't come up with much so I thought I'd post it here.
We are on 11sp1a

Editing a Run Script Action that is currently VBScript with :-
script file extension = .vbs
path to script engine = ${WinSysDir}\wscript.exe

As soon as you click on edit and bring up the script editing window the above
entries are blanked and you are left with
script file extension = .bat

This stays even if you cancel out of the script edit window.
Not sure if this is just a glitch in our environment or more widespread.

Greg K