Here is a small sample from some other mints (I have load but won't inflict some of the lower interest coins).
This one is an oddity:-
Constantius II - AE2 - RIC VIII Aquileia -
Obv:- D N CONSTANTIVS P F AVG, Pearl diademed, draped & cuirassed bust left, holding globe in right hand, N in right field
Rev:- FEL TEMP REPARATIO, Emperor bare headed & in military dress standing, holding standard with chi-rho on banner in his right hand, resting left hand on shield, two bound captives in Phrygian helmets standing, facing each other before him
Minted in Aquileia (//AQP Dot)
Reference:- RIC VIII Aquileia -
Looking at RIC there are three issues for this type at Aquileia.
The first has no letters on either side. The captives are described as standing and would have AQP:dot: in exe. - RIC VIII Aquileia 107
The next two both have N behind the bust and an N in the left field on the reverse with the captives described as kneeling.
With AQP in exe this would be RIC VIII Aquileia 119 and with AQP* in exe this would be RIC VIII Aquileia 120
My example seems to be a mule from the later issues with letter behind the bust and the earlier issue with the captives standing but with no letter on the reverse