If the supervisor instructs the contractor to carry out work which is not as the works information. The contractor issues an EW as he knows it’s a incorrect procedure. Is this recorded on the defects list as a clients defect?
In the ECC the Supervisor has no authority to instruct the Contractor to do anything except search for a Defect. Only the PM can instruct changes to the Works Information unless they have specifically delegated this to someone else in accordance with the contract.
The Contractor is right to notify this as an early warning as it could affect the performance of the works in use if you did what the Supervisor said. There is no such thing as a “client defect” in the contract assuming you mean the Employer (or his team) are not acting in accordance with the contract.
The early warning notification should trigger a risk reduction meeting with the PM and it would be a good idea to get the Supervisor along as well. In this forum you should discuss the issue that the Supervisor has with the work and seek an instruction from the PM if it is to be carried out differently from what the Works Information states.
One thing to watch out for under Option B (although the principle applies to all main Options) is that the BoQ does not specify materials and standards etc like it would in a traditional contract. As Contractor you are obliged to “Provide the Works in accordance with the Works Information” not the BoQ.