API-launched ads: Different audiences, sudden drop at midnight?


Hey - unsure if this is due to being launched from the API, or just a general ads issue, but it seems like our ads go from a sizeable pile of impressions at the 11pm hour to 0 impressions at the midnight hour. Two different tailored audiences:

Do things reset at midnight / take some time before starting to hit up our daily budget? Any advice is appreciated, thanks!