An “unique” Domitian As/Dupondius?

[Multatuli]

This coin is seemingly an almost "unique" Domician As/Dupondius.
A friend of mine 4 years ago offered me the coin reporting it as a unique coin of this type, apparently not referenced in any known source. Of course, I also went to research about it, and what I just found was an account of an Italian numismatist about a similar piece in a FAC report in early 2009 (in italian, not a big deal for me):
https://www.forumancientcoins.com/monetaromana/corrisp/a564/a564.html
It was probably struck at 80-81AD by Titus, still being Domitian as Caesar. Here are the likely legends:
CAES DIVI VESP F DOMITIAN COS VII
CONCORDIA AVG / S-C
What is striking is that there are coins of Domitian with Concordia sitting, but here she is standing. In the same period, there are coins with standing Pax, Minerva and Ceres, however, I found no other records of Concordia (besides the Italian report in 2009).
Apparently, is not seems to me a hybrid coin or mule. 
Up to now, I don't have neither the weight nor the diameter, because I’m traveling and not in my home, but it´s looks like an As, much more likely than a dupondius, but sometimes dupondii struck under Titus can be laureate. 
When I acquired it, I spoke to our friend @David Atherton, who also no found references or other known examples. But that was a long time ago, so I'm asking you and him if anyone has any news of any other known/referenced specimens.

The only reference found in internet is on the Wildwinds site, posted before I purshased it, by my friend Alex Laud, the former owner. 

 

Domitian AE As. AD 81. Possibly an Eastern mint.
CAES DIVI VESP F DOMITIAN COS VII, laureate head right.
CONCORDIA (AVGVST?) S-C, Concordia standing left, holding patera and cornucopiae.
Cohen 70 (Vesp) var (this reverse for Vespasian); Cohen 42 (Domit) var (Concordia seated); BMCRE 558-560 (Domit) var (ditto).

Thanks in advance!

Edited January 30 by Multatuli

[David Atherton]

No luck on my end for locating another. I'm now inclined to think it's a mule and appears to be a dupondius, based on the colour of the metal showing through the patina.

[Multatuli]

Thank you very much, @David Atherton! The possibility you raised that it was a mule is the most likely. You are completely right about the possibility that it is a dupondius, because the appearance of the coin is actually more orichalcum than copper. Even the other coin described as As by weight (8.97g) also has an orichalcum appearance. But they do not appear to come from the same die, although the conservation status of both is quite compromised, especially the other. But I need to weigh it to evaluate better.

Here is a comparison of the known 2 coins:

Edited February 1 by Multatuli