Not sure how you’re keeping the camera updated or what the set up is like.
I can only assume that you have a Tick event that updates the camera position or/and you use Inputs which also fire all the time and try to keep the camera at a specific location. The whole process is then interrupted when you start dragging and manually override current camera movement. I’ve just tested onDragOver and it fires every frame even if the mouse is still.
What you could try doing is to have one centralised location where you tell the camera what to do. Let’s say in the PlayerController:
And then ensure that the only thing you ever update is the DesiredCameraLocation. The tick in the controller will handle the smooth transition.
If you want to use draggable widgets to control the camera this is quite unlikely.