Because of the quickly review.
I've known BS to review images while I was uploading the batch a few years back. The other explanation is they have too many reviewers at that time so no queues.
Maybe I need to go back to uploading at 3AM like I used to. Insomnia is good for something? Unless that means I'll get offshore reviewers, clicking for quotas who tend to be fast but random.
By the way, SS reviews have been running around 24 hours for me this month, Editorial or creative. AS around the same. Not like the "good old days" when we'd see 5-7 days as normal.