I was on error ref and you'd have to check it with another dime . Have to check the thickness of the outer rim and the reeding . I can see the thickness of the outer collar but not sure on the reeding
I did the first time I checked it, it seemed normal. After reding your post I checked again and there is a slight extra thickness in areas.
Thanks, As I posted above there are some areas that are slightly expanded mainly @2 and @7. The reeding is not broken. So, maybe just a weak and expanded collar.
A wide collar, as @Rick Stachowski suggested is a good possibility. If I understand correctly, a wide collar can be stretched and not necessarily broken.
Ya know I would have just tossed that one into the spend jar, if it wasn't in high AU/MS condition. I wouldn't have even looked twice, but it jumped out as look at me. LOL
1985-D dimes are notorious for poorly struck design rims, especially on the obverse. The poorly struck rims are teamed with an especially well-struck edge. It's the result of excessive die convexity (mainly on the obverse die) and inadequate planchet upset. The OP's specimen is actually relatively well-struck compared to other specimens.