British coins die wear and die flaw on Victoria Sovereigns

In the internet, recently I found a 1872 Sovereign for sale, with an error in its lettering: the "T" in "VICTORIA" shows an "extension" on its outer side. The same 1872 coin shows another structure similar to a line on the bottom part of the neck of Victoria near the "1" of the date. I compared it with my own 1872 Sovereign which doesnot exhibt such structures. Please look at the fotos added.
From the die numbers of the 1872 shield type sovereigns and from its mintages I concluded that with one set of dies up to 100.000 coins were struck. This leads to think about wear of the die sets during usage. Therefore it seems probable that near the end of an usage period the dies had damages such as cracks. Could that be the cause of both feachures visibles on the 1872 Sovereign for sale (at the "T" and on the neck of Victoria)? Does anyone have an idea?
Thank you very much in avance
Ralf
Comments
..and I have another example: a have a Georg II 1745 Shilling (left side of de added foto) which exhibits a "banana-shaped" overstructure from the center to the hannoverian shield of arms. The right side of the foto shows another 1745 Shilling without that overstructure feature. Does anybody have an idea for that?
Ralf