I been sitting over this nearly 4 hours and can't solve that issue.
The problem is, that newly created comments will not get displayed after submit was clicked, not even the message "comment has been posted" does appear either. Instead it shows me an new empty comments entry form. They get shown when I reload the page. If I answer on an existing comment, the answer is shown after submit and also the message does appear. So that works as expected.
I use the production release of the comments module (7.x-1.0-alpha1), also installed the development release (7.x-1.x-dev) just to see if there's any change in behaviour.
I know there been almost similar questions regarding this problem, but none of them seem to help me. I also installed the "block_refresh" module as suggested in another question, but it does not help either. Even though it is for block refreshes, so I actually didn't expect this to work (I just gave it a try).
I use the comments on a news page (created a news content type).
So if anybody could give me a hint where to look or what to change, test, etc, would be greatly appreciated. I know my problem description is not very helpful, but maybe somebody ran into the same issue and can give me some ideas.
Thanks for helping out!!