Hi RR. I’m not able to replicate- but it may be a version issue. I’d suggest updating to 2.4.0 to eliminate the possibility that’s the problem.
Also- I want to be sure we’re testing the same way. I made an entry in my test forum by ‘test1’. Then I logged into the CP as ‘rob1’ superadmin and made a blog post. On the forum tab- the ONLY field I changed was the ‘Forum Topic ID’- I put the id of test1’s topic. (Topic, not reply.) After I submit my new entry- I checked the forum- and the forum topic still shows ‘test1’ as the author- and the entry dates for the channel entry vs the topic are different: 02/29/12 04:02 pm vs 29 February 2012 03:56 PM.
I didn’t spot a bug fix in the forum by skimming for ‘forum’- ditto skimming the first page of results in the bug tracker when I searched for ‘forum’. That said? I’m not replicating. So an update is a good idea. And if you spot how my testing differed from what you’re doing, just let me know and I’ll retest.
From here- I’m just not replicating, so I’m leaning toward a version issue. Make sense?
As to switching the author back? There is no current way to do it via the control panel, at least not in the above situation. If it’s a critical issue? I can walk you through doing it via direct database manipulation- but you’ll definitely want to backup your database before we go that route. You’ll also want to know the member_id of the person you want to re-assign the topic to.