Sounds like a problem with:
1.Your stroke path and
2.The timing and direction of pull of the double haul
Your stroke path over the years has become grooved for the faster fly rod. A faster fly rod bends less, which means it shortens less for a given energy input. It maintains the length from the rod tip to your hand.
In the illustration below, notice that the rod tip approaches the casting hand as the rod bends. To compensate, the stoke path is convex
with the convexity of the stroke path compensating for the rod shortening.
Now imagine a softer rod bending more but the stroke path staying the same. The stroke path fails to compensate for the rod bend and you get a concave rod tip path, which leads to a tailing loop.
So the stroke path that you are used to results in a concave rod tip path which results in a tailing loop.
Now you add a haul, which causes an even greater dip in the rod tip and causes a worse tailing loop.
the zing, zing, you are hearing is because the your haul is at a steep angle to the position of the of the stripping guide. The direction of pull should be along the axis of the rod guides, so the fly line is not pulled around the the stripping guide but along the stripping guide. Look at the illustration below and not that the direction of pull is along the rod axis so the fly line is not pulled around the 1st stripping guide.
Now view the video below and see that the direction of pull is changes to accommodate the rod position of the backcast haul and the forward cast haul.
You are not going to like my recommendation. If I am correct, I would trade the rod for a faster action rod. I think you would be much happier.