Hey guys so listen this documentation is incomplete https://shopify.dev/themes/tools/cli/theme-commands. Especially part about Shopify theme serve. This part “Development themes are deleted when you run Shopify logout. If you need a preview link that can be used after you log out, then you should push to an unpublished theme on your store.” It is so unclear what this means. This needs to be more clearer.
When we are using Shopify theme serve we need to make sure after we are done with all of our changes to do a Shopify theme pull of development theme either after Ctrl c or in another terminal and push it into unpublished or published theme to keep our changes from development. I also want to note that something happens when we close the theme with Ctrl C and pull from development sometimes it does not pull or looses data without running Shopify logout and on next serve it looses all the data.
It is sporadical and the only way i found this working every time is having the serve on and then pulling in another terminal periodically. Anyway I hope this will help someone and please do your documentation correctly…