the B in the reverse field is retrograde or engraved over... like S over EI in an attempt to change it to BI or maybe someone thought SI was another workshop.
Maximinus II
A.D. 312
20x21mm 4.2g
IMP C GAL VAL MAXIMINVS PF AVG; laureate head right.
SOLI INVICTO; Sol standing left in long robe, right hand raised, left hand holding head of Serapis; BI in left and ✶ in right field.
In ex. ANT
RIC VI Antioch 167b