IF Node → Merge Node: No Merge Data Found

Note - I realize in the simple example above, I could add a No Operation or some kind of work around and only test the FALSE path.

However, what happens when both paths contain different logic, like this scenario:

Somehow, when I test this, it uses test data from a previous run of the FALSE branch, but that causes later code to fail since it relies on an earlier node that is no longer present in the stunted FALSE branch.

Is there any way to stop Merge from waiting for both inputs?