Antoninus Pius AR Denarius. Unlisted One Or Mule?

Hi! If you are sure about its authenticity, then it certainly looks like a mystery to me.

I have never seen a DIVVS ANTONINVS coin stating on the reverse how many times the deified emperor has been consul.
My experience of course, is very limited compared to other fellow forum members, so I recommend waiting for more opinions.

The first coin, RIC 137, has been struck from 145 to 147 AD. That means, it ceased to be minted 14 years before the emperor's death. Perhaps they are not the same reverse dies as in the DIVVS specimen? Otherwise, quite odd.

Both coins appear to be fourrees. The copper core is exposed on the left coin. The lumps in the field on the right coin are likely blisters where the copper core is corroding below the silver plate. Sometimes the counterfeiters mismatched obverse and reverse.

I'd wager it is probably an imitation - Not sure whether it's a fourree or not, but the mint shouldn't have still had the thunderbolt-over-altar reverse dies by the time Pius had died, so a mule is nearly impossible.