There was a thread a week or two ago where a moderator stepped in and issued a non-warning note after someone corrected someone else’s typo within their own quote box (“Bob Dylan” had been misspelled as “Bob Dillon,” and the second poster corrected the first’s so that it was the proper Bob Dylan.) I can’t find the thread and it’s not worth searching for, but:
IMHO, such corrections ought to be allowed. They are not changing the spirit of the other poster’s intent in the post, and enhance the clarity (if someone misspells Joe Biden as ‘Joe Bidne’ due to fat fingers on the keyboard, there’s no reason that it should be continuously quoted subsequently downthread again and again as Joe Bidne.)
Where such corrections would go wrong would be if someone is inserting their own agenda into the correction (i.e., changing “Bush’s war in Iraq” to “Bush’s war for oil” or, “The Universe is 8,000 years old” to “The Universe is billions of years old”) - that’s obviously unacceptable since it’s changing the poster’s intent. But minor typos should be perfectly permissible to edit.