This depends on the round trip. The behavior was designed together with users in the past. You can have a look here. If you are close to your destination and ask Kurviger to recalculate the route, how is Kurviger to know which waypoints you want to skip and which to keep, it makes sense that Kurviger will recalculate a route to your destination in this case.
This is especially critical if you use the same road in both directions. Either Kurviger can skip waypoints or it can’t. Users clearly prefer to be able to skip waypoints, so that’s the behavior of Kurviger.
You can always choose to place your own waypoints close to your current location by hand to extend the round-trip to your own liking. Just long press the road ahead and place an intermediate point there, this might keep the route closer to your original route.