Coinsandcanada.com

The first coin of this set shows obverse die deterioration and the second coin shows that the obverse die was replaced. The reverse die chip/crack on the C of Canada stays consistent to prove the obverse die was only replaced.
Coin 1:
Photo 1 -reverse die chip/crack on the C of Canada
Photos 2,3 & 4 -obverse die deterioration of Regina, Elizabeth and 25 cents

I will put the Coin 2 photos in a reply.

Coin 2:

Photo 1 -reverse die chip/crack on the C of Canada identical to coin 1
Photos 2,3 & 4 -obverse die has been replaced and Regina, Elizabeth and 25 cents is back to normal