Occurred once, haven't reproduced it since:
Sov Airborne Guards (Terror Tactics Commander) upgraded with the double DPs (100 muni I think?) were able to be upgraded with yet another DP for 40 munitions on the button where usually the smg upgrade lies. That was super weird? It had the DP icon as well. It looked so intentional but I could not find anything about it in the patch notes and couldnt reproduce it in a bot game...
Edit:
Afaik Airborne guards get 3 DPs, you sure they didn't drop one in combat? The single DP upgrade appears in that case.
Thanks! I thought they get two, but that would explain this! I'll test this.
2nd Edit: Indeed, they get three, but the tooltip is wrong (says 2).