That is because you changed the original chinese title into “Global Cloudflare Outage”, not the english translation of it. Using the pencil in the post menu makes it easier to see the distinction.
You also completely the title language, which would need to reset the whole language detection into translation flow over again.
I guess the bug here is that the quick edit for title / category / tags doesn’t support the popup for picking which locale needs to be translated. As this can get quite tricky, I propose that we disable the whole quick edit when viewing localized topics. When clicking on the pencil for quick edit, it should popup the locale picker modal and open the composer for the OP.