Acknowledged mistakes (6)
I believe the answer is:
errata
'acknowledged mistakes' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for errata that I've seen before include "List of text corrections to be made in a publication" , "Printing corrections" , "Mistakes in printed matter" , "Feeling nausea" , "Noted mistakes" .)