Normal? A consequence of getting old and losing angulation above the hips? Work on getting rid of it or don't worry about it?
Just as a matter of geometry, if you keep your legs the same distance apart, the skis will be further apart on the snow when angles are larger.
...it could mean you have some weight on the inside ski which thus grabs... this is usually a self re-inforcing cycle: you step into the turn too wide, thus end up with some weight on the inside ski, which diverges even further.
Check the top of the turn. Are you moving the inside ski inside, too eagerly?
basically your saying your tracks are narrower at the transition?
Are you tensing the outside leg to resist the forces of the turns?
Are you trying to shape turns with the outside leg knee joint closing?
It sounds like your outside ski may be diverging as you finish your turn. Would this describe what is happening?