The petition must describe the actual work-site arrangement. Work at a customer's location is permissible only if the group's U.S. entity, not the customer, controls and supervises the employee and the work is not simply supplying labour.
Fix the order of events
When the site changes, stop and re-sequence rather than filing on the old plan. Hypothetical example: a Lévis marine-electronics firm planned to have its integration specialist work at the U.S. affiliate's own workshop, but a customer now wants the installation done at its yard for eight months.
Before filing, obtain the customer contract and check who assigns tasks, who evaluates performance and whether the specialist's work is tied to the group's own product. If the affiliate retains control and the work is about the group's system, the petition can describe the client site truthfully. If the customer would direct her day to day, the arrangement resembles labour placement and the plan needs to change before it is described.
Then rebuild the timeline: contract revised, assignment letter rewritten, filing, processing time, arrival. Filing first and correcting later is slower than getting the arrangement right once.