When you tig weld end to end of a piece, it creats a thin spot where the weld ends. By leaving material untouched on each end of the weld the tab end strength is stronger and eliminates chance of tab end cracking .
@JesseM to answer your question.
A tack weld would be a spot weld to hold two pieces together so they dont move while you perform a weld.
The weld in question measured 3/4" (19mm) in length.
Its job was controlling tortional load between the clamp collar and tab end. The tab end is constructed as a ring that is threaded and supprted arround the hanger.
On the new part the weld measures nearly 2" in length with no weld end point on the rod mounting tab side.