This first coin is an example of the coin without the question (just for those that are not familiar with the type!).

Probus Antonianus
Obv:– IMP C PROBVS P • F • AVG, Radiate, cuirassed bust right
Rev:– TEMPOR FELICI, Felicitas standing right, holding caduceus and cornucopiae Minted in Lugdunum (I in exe.) Emission 6 Officina 1. A.D. 278 - 279
Ref:– Cohen 713. Bastien 269. RIC 104 Bust type F
The second coin is the errored coin.

Probus Antonianus
Obv:– IMP C PROBVS P • F • AVG, Radiate, cuirassed bust right
Rev:– TEMPR FELICI, Felicitas standing right, holding caduceus and cornucopiae Minted in Lugdunum (I in exe.) Emission 6 Officina 1. A.D. 278 - 279
Ref:– Cohen -. Bastien -. RIC -
The O is missing from TEMPOR. This reverse error is known on a single die and there are two known examples (this being one of them). The other example is linked with a different obverse legend variety.
Errors happened with ancients too though they are in general quite scarce.
Regards,
Martin
