What the law requires
Regulation (EC) No 852/2004, Article 5 requires HACCP procedures to set corrective actions for when monitoring shows that a critical control point is not under control. The same article requires documents and records that fit the nature and size of the business. In the UK, the Food Standards Agency pack Safer food, better business has the same kind of record in its diary, where you write down what went wrong and what you did. The limits that call for an action and how often you review the log come from your own HACCP plan and the national guide.
Every problem needs an action and a signature. At an inspection this shows that you noticed the problem and dealt with it.