This is because ads are never targeted to you directly, but to buckets (audience segments).
If you buy something, you might land in one of those buckets.
Advertiser can buy impressions to those buckets.
The buckets are not refreshed on a daily basis (depending on the audience provider), and therefor can contain stale data.
If you buy something, you might land in one of those buckets. Advertiser can buy impressions to those buckets. The buckets are not refreshed on a daily basis (depending on the audience provider), and therefor can contain stale data.