this sounds like an old conversation from many years ago and I'm not 100% sure that some solution for such a thing might not actually now be in AC
Yes, it is an old conversation, but no, it has not been addressed.
I agree that this is an issue; speaking of Tahoe (in another concurrent thread), it was discussed with Jon B a at that time, and he is certainly aware of the issue. Sounds like it is "on his list".
There are several potential ways to improve the way AC deals with this. I have always favored creating an option to "strike through" erroneous text, as you would do with a paper chart. If the entire note is an error, where it appears in the list of "Past Encounters", the strike through would appear there, too. In that way the error and correction would always be included in the record, but it would be clearly visible as such.
I also agree that MU has added a level of urgency to this. The current system means that everything in a note entered in error (even if it is "deleted" in an addendum) is counted incorrectly towards the MU criteria. This will mis-represent your data either in your favor OR against you, but always inaccurately.