Maybe, but I don't see his motivations. At this point his character just comes off one needed to counter all the angst, and is more "normal" in terms of their emotions in comparison to the Royals who are always on guard, Lucaon who is understandably closed off, and Kyon who is now just guilty, timid and submissive which is also understandable given his own history. Given that it was a previous non royal servant who put the poison in Lucaon's family wine the last time it would seem a bit obvious and repetitive to have another servant do the same thing again, just with tea.
Even Kyon was normal...he himself didnt know who he was...so could be Logan. Just because he acts normal doesnt mean he is normal
I think it's Logan. Because he is the newest servant .of lucaon's home. And if it is him I think he has a master who is running the show probably the same guy who was using kyon