Wouldn't really describe this as a "bug", lol. But - same here, I'd really love to still be able to use display-panels inside compact circuits - not as circuit components, but as icons and notes and titles. I use them heavily in my builds for annotations, to-do lists, checklists on blueprints, rates, icons calling attention to certain areas, and so-on.
I spent today implementing this for myself; if you'd review when you have a chance, I'd adore it: https://github.com/Telkine2018/compaktcircuit/pull/58