You planed our top and now it’s cupping. Now what?

This happens to us as well. With live edge slabs, planing them does not guarantee that the slabs stay flat. They will be flat immediately after planning, but over the course of a few days some movement might occur. Many reasons that can affect it include removal of the material that held the slabs prior and change of the grain structure. We often add C-Channels or add under-the-top kerf lines to ensure the end product stays flat indefinitely.