As a licensed Architect you take an oath to abide by at all times. There is a lot of responsibility an Architect has, and for all the work they do, they will be held accountable.
A common issue with the owner having independent contract with the Architect and another with the contractor is disagreement and lack of communication. Because the owner has a contract with the Architect and another with the contractor, the only contract broken was between the owner and the Architect. Once the owner went around the Architect to make changes to the design of the cement, (s)he broke the contract. The contractor did not break any agreement between them and the Architect. Because of this, the Architect should immediately contact their lawyer and explain then matter. Owners are not Architect, so nor should they make decisions like them. All the owner saw was more work done and less money spent, and this is a common desire among all of us Architect or not. However, financial shortcuts in this industry usually means shortcuts in job quality and breaking the laws.
Regardless of why or how this happened, the Architect should report this matter to the D.O.B, their lawyers and not sign the requisition before them for the job done.