Just to be clear for all readers, somehow you had to have used a Variable with the name of "TriggerValue" in order for it to show up in the Variable list. Maybe it came from an imported Macro.
IAC, here is a screenshot of the "Insert Variable by Name" tool in my KM account, which shows no such variable:
Note that all of the Variables that start with "Local__Trigger" are variables that I created to explore/document the various Trigger tokens.
There is often confusion between KM Tokens and KM Variables.
Please see