I observed this behavior in LabVIEW 2016. A simple example that you may use to reproduce this is attached.
I created a dynamic dispatch method (Open) in a parent class (Logger). In a child of Logger (Event Logger), I created a method (New File with Header) and placed the parent method Open on its block diagram.
If I right-click on Open and choose Find Callers, Open is not found. If I change Open to a static method, then Find Callers is able to find it.
My primary question is: Is this behavior intended?
Secondary discussion: Perhaps creating a dynamic dispatch VI, not overriding it, and using it in a child method is not an ideal approach (if so, LabVIEW not finding its callers is a subtle way of enforcing the point). Alternatives are to just make it static instead, or to override it with a child Open that simply calls the parent (Find Callers is able to find it in that case as well). I am open to your opinions about this.