I think I found a typo in some information on one of the learning pages.
IS SHOWN LIKE THIS
/** React to a trigger volume activating this object. Return true if the reaction succeeds. */ UFUNCTION(BlueprintCallable, BlueprintCallable, Category="Trigger Reaction") bool ReactToTrigger() const;
SHOULD BE
`/** React to a trigger volume activating this object. Return true if the reaction succeeds. */
UFUNCTION(BlueprintCallable, BlueprintImplementableEvent, Category=“Trigger Reaction”)
bool ReactToTrigger() const;
`