Why does "Terminal" get replaced with "Applet" in AppleScript?

Why does "Terminal" get replaced with "Applet" in AppleScript?

I have a simple AppleScript (packed as an app) that tells the Terminal to
execute a couple of lines of code. Every so often -- about once every 7 to
10 days -- after a cold restart, the code has been "corrupted" somehow and
the word "Terminal" in the Tell statement has been changed to "Applet" and
the "do script" commands have been replaced by "«event coredosc»". I've
been fixing this by just clicking edit on the error prompt and pasting in
the right code for the app. Has anyone encountered this before? None of my
other AppleScripts (also packaged as apps) that tell the Terminal to do
things has this problem. Does anyone know how to fix this? I've also tried
re-typing the app's sourcecode from scratch in a new AppleScript app and
no dice.
I am using OS X 10.8.4.