(I moved this post to the category of Meta - the place to talk about the forum itself)
Yes, I've noticed this as well. I typically bang out a reply, do a quick edit pass but then go back much later for another edit pass, as I know I'm not the best speller/grammar person and these posts stay around forever.
I did a bunch of those last night, so all of those posts appeared as "latest" again.
I looked through the settings but did not find a way to totally prevent that from occurring. I did change one setting that will allow people to go in for 10 minutes after they create the post and it will not show as updated. The previous setting was 5 minutes. I could make that even longer I suppose.
I will go to the forum folks website and see if there is anything else I can do.
Overall I agree with you, this is the best forum software I have ever used... but everything can be tweaked.