There's a separate log in the backend which records every interaction out to IFTTT. Below are the recent log times for that particular webhook. The times are in UTC, so you will need to adjust for your timezone.
Given the way this adjusts every day I believe the trigger here would be sunset.
There's no record of a call out to IFTTT near midnight your time. Are you sure this end point hasn't been used somewhere else as well and could be triggered by some other service?