I am building a project in tiptap and I’m facing an issue where I cannot type anything when collaboration cursor is present in an empty codeblock. Even in tiptap’s live demo, the same issue can be seen. Tiptap block editor template
This is a TipTap issue, not ProseMirror, I don’t think you’ll get a definite answer here.
If you want to solve this take a look at https://prosemirror.net/examples/codemirror/ and https://prosemirror.net/examples/collab/#edit-Example
My feeling is that you’ll have to extend the Selection mapping case so that it handles cursors in codeblocks, which can be tricky, especially if you use YJS.