I don’t think I would have read “Circle Back” that way, but definitely can see where Siorn is coming from. It occurs to me it might make sense to flip the phrasing to something like “Make a copy of the first perk you sell each round.” Does that have the same ambiguity?
The only edge-case I can think of there is that after you buy Circle Back, it will still duplicate the first perk you sell after you bought Circle Back - even if that’s not the first perk you sold that round. That might not matter too much but I thought I’d mention it.