It very well might. Continuity is mentioning events from past installments. Spock's Pon farr or Data's creator's name. An arc is a storyline or character's development that progresses with each installment. The "trial of humaity" is neither. It was rarely referred to over the course of seven years. It pops up as part of a bookend.That would mean that my skills in English, which is not my native tongue, played tricks on me.