I did a quick run-through of my hone cities after patch 1.0.11 and found that several units and mercenaries are missing portraits, they just show black boxes.
I ran through all civilization home cities and saw that the following units were missing portraits.
- Hapsburg Pandur
- Hapsburg Magyar Hussar
- Mercenary Bosniak Lancer
- Ethiopian Oromo Horseman
- Dutch Flankeur
- Haitian Picket
I hope this helps the team out. Happy bug hunting!