I don't think it looks like any of the rim is missing! Can you take a picture of the edge in that area? From the picture you provided I think it's just PMD!!!
A thought occured when I was posting it! Wasn't for sure. Thanks for informing me. A little to late to edit now.
Appears to be a worn die issue. Could be wrong, so maybe others will chime in. @paddyman98, @JCro57 ??