You misuse the "Declare Typing Context Unchanged" directive

There is no point to use the {DeclareTypingContextUnchanged} here.

You simply should have: qtc => QTc

Then try your expansion in Notepad.

If it works there, it probably means that you have some feature in Word that is interfering. Then you need to find out which. You may also try.

qtc => {PasteText}QTc{/PasteText}

Forcing the expansion through the clipboard, you may get rid of the interference that produces Qtc instead.