Think it's at least the second time, might have showed up for the personal time part of the school trip and maybe showed up again when Tomoko was wandering around and coming across her few speaking-terms acquaintances with their own friend groups at the school either before or during the sports thing.
the last comic reminded of how much progress tomoko has made so far in the story, she used to barely be able to speak to strangers and now people are talking to her normally it's kinda weird to think back on but very wholesome im glad