Why does it go from 11am to 12pm? 

Shouldn’t it go from 11am to 12am and then reset at 1pm?

Growth Lead at @yup, an app where you can crosspost to Farcaster, Twitter, Lens and Bluesky at once and enjoy their aggregated content

replace 12 with 00 and it makes more sense

It's the result of having a 12-hr clock. Ante Meridiem "before mid day" (AM) = from midnight (12:00 AM) to just before noon (11:59 AM). Post Meridiem  ("after mid day") (PM) = from noon (12:00 PM) to just before midnight (11:59 PM).