People always have said this from when I was in ad tech over a decade ago and to be honest, I think it's much more mundane: a delay in the ad tech data pipeline. If you have delayed intent signal, or you have delayed suppression, or even if some conversion gets dropped in the pipeline, you're going to get this effect. People talked about this a lot but almost all the focus on recent purchaser lists was on suppression. So I'm just going to go with the boring explanation: data pipeline error.