Residence alone does not authorize the work. Assess the actual U.S. activities and applicable immigration requirements before relying on the proposed schedule. Ask what the company has settled before asking what the individual may do. Which entity employs the person during the U.S. periods, which entity directs the work, and whether the receiving entity stands in a qualifying relationship with the foreign employer — those three answers come first. Residence, payroll location and the frequency of return trips sit downstream of them and decide nothing on their own.
Use physical location and actual activity
Identify what work occurs in the United States and for which entity. Neither frequent returns to Canada nor a remote-work description replaces a qualifying basis for the U.S. assignment or the L-1B knowledge requirements.
The governing conditions are stated plainly enough to test a plan against. L-1B requires one continuous year of qualifying employment abroad with a related entity within the preceding three years, specialized knowledge of the organisation’s product, service, research, equipment, techniques or management, and a U.S. position that uses it.
Maximum stay in L-1B is generally five years. None of those conditions bends because the employee sleeps in Canada. Where the U.S.
periods are short, the question is still what activity occurs during them: paid productive work for the U.S. entity is work, whatever the trip is called internally. Have the actual activity characterised before the pattern is repeated, not after a pattern already exists.