I believe that there is agreement that bugs in the code posted in questions should never be corrected by editing by anyone except the OP (and that even edits by the OP should be rejected if fixing the bug changes the question into another question, rendering existing answers invalid).
But what about bugs in answers? My procedure so far is not to edit, but point out what I believe is a bug in a comment and leave it up to the author to correct, or ignore.
But I've noticed that answers are being edited to fix bugs, and that those edits are apporived by > 3000 rep. users.
What is correct protocol?