Agreed. The plugin link goes to their github, where it says it was archived by the owner on Nov 2, 2024. And the current version is from may 8, 2024. This is an active fork of the original, but replacing the original plugin with this one causes existing blocks to be invalid.
Fixed it. The problem was this old plugin because it has added additional ‘underwater’ tags to code blocks. By deactivating it, all code blocks became invalid and I had to run some database update queries to remove the excessive code.
