Blame Salvini.

Jarkon's sadness is not just because he is in chains and will soon be sold as a slave. No. His sadness is because he will soon become a slave all because he was doing something that he did not care about and didn't want to do in the first place. Who wouldn't be angry because of it?

Even If he were not a slave, he would not be happy that he found another trace of Soverick. That only means more work for him. But now he has more work that he cannot do because he is a slave and more work that he can't refuse because he will be a slave. 

He muttered to himself, "I blame Salvini."

Even the other battle sage monkeys who believed in the importance of their mission agree with that sentiment just a little bit. They didn't curse her as Jarkon did, but they are of one mind and they nod occasionally in agreement whenever he curses her.