The Journey panel will store all the instance you visit. If you jump back in your journey, you’ll still see the path ahead (the forward history). If you then decide to take a new path, the history creates a copy of the current instance and builds a new path from there. The idea is you can see all the instances you’ve visited even if you jump backwards and forwards. So yes, sometimes you might see a duplicate instance in the history as the start of two different paths.