If you want an honest answer, the discrepancy is two-fold:
1) I somehow completely missed the reference of Vicente Orloff being around in 2991, since my PDF copy of the original Marik sourcebook wasn't text searchable. I believe I saw that he was head of the duchy in 3025, but I figured thirty years ago would be a completely different story, and I couldn't find any mention of who preceded him.
2) Because of the time crunch in getting Counterattack ready to make a Gen Con debut, we didn't have time to send "High Value Target" to fact check. Given that the story was set nearly thirty years before the Fourth SW started and it dealt with a relatively small FWL faction in a sparsely covered part of history, we didn't expect to run into any problems, and I'd done as much fact-checking as time allowed during the formulation and writing of the story.
One way to explain this discrepancy would be this:
Vicente is a cousin of Reinhard and Skylar Orloff, and his father (who I believe is unnamed?) still had some political pull but was removed from the line of succession due to estrangement or some unforgivable slight. In the story, you might notice that the characters all refer to the head of the duchy as "Duke Orloff," not "Earl Orloff."From Orloffian perspective, an earl can't head up a duchy: it'd be called the "Earldom of Orloff" if that were the case. So Reinhard and Skylar style themselves as "Duke," much to the nobility's dismay, and Vicente's father, technically an earl under Reinhard despite the estrangement, still has the Captain-General's ear, and thus so does his son—hence why he was invited to dine with Janos Marik in 2991. A lot of legitimate dukes in the FWL don't take kindly to Reinhard's arrogance for using the title, so when Reinhard is killed by a Maskirovka assassination (which was designed to give the CCAF leverage for the attacks on Tsinghai and a failed thrust into the Duchy of Orloff) and Skylar the buffoon takes over the duchy as "Duke," Reinhard's enemies seize their chance to exert political pressure on the duchy and get "Duke" Skylar stripped from political power (or assassinated by rivals, perhaps?). Then Vicente's father is installed as the proper "Earl of Orloff."
There's a whole story there just waiting to be told, if you ask me.
Does that help?