Yeah, Ambrose got a second DSO today - since the program doesn't seem to be able to award bars to medals (DSO with 1 bar, DSO with 2, etc.) for subsequent awards of the same medal it just gives you another one. I'll describe that as a bar in his letter home, and if he gets a third, as a second bar. But that's as far as the bars go, near as I can determine, so if he gets a 4th, I won't mention it at all.
My Briff pilot has two VCs, two DSOs, and some other stuff - all in 6 weeks at the front. I put him on pause when I started the Centenary Challenge, so I don't know how many more of each he might get if he'd kept on the same pace moving forward.
It may be a bug, or it may just be how the program handles medal eligibility. A couple of DSOs, to represent bars, are okay, and even a second VC instead of a bar for it, which is what actually was issued.