This coin w/ this VOT/IS/XX K3 bust STR· mintmark is unlisted in RIC. There is a PTR· mintmark and VOT/IS/XX on altar known (as previously marked by Helvetica), but this one is the first one I see from 2nd officina, making this a distinct issue instead of a variation of Trier 342. Should be between Trier 342 and Trier 343, maybe?
Other examples are needed to confirm though.
(Unfortunately picture is not that good, you can still see the dot after the STR, unfortunately the area in front of STR has had some pitting problems)
AE3 20mm 2.35g
AV: CONSTAN – TINVS AVG; laureate, wearing trabea holding eagle tipped scepter in right hand bust r.
REV: BEATA TRAN *** QVILLITAS, altar with globe, inscribed with VOT/IS/XX
EXE: STR· Trier mint.
REF: RIC VII Trier – unlisted