Interesting, yeah, we were doing something closer XP, not Scrum. I've never done Scrum. Haven't done "agile" in the last 10 years, as it's not really a thing where I work now.
But yes, in XP, the 'customer' or 'product owner' would not attend a daily standup. The purpose of the meeting was for developers to sync and maintain velocity and social and work cohesion.
Meeting with customer/PM was something that happened at the end or start of iteration.