I posted a question a few years ago, but this is a different issue. This is a block of four, lower right corner, and probably Carmine and Pale Yellow Green, making it ACSC D107A. The question involves a frame plate issue above the R of Australia. I don't see it listed in my ACSC catalog, though I only have the 2014 edition. Here is the entire block:
Here is the lower right stamp, showing a small indent in the frame just above the L in Australia. This is normal for this issue and is seen in every stamp.
However, the upper right stamp appears to have an additional indent in the frame, just above the R in Australia. This is not listed in my ACSC. Ideas?
Note that it also contains a small dimple in the lower left side of the Value Plate which is probably variety (VP)e