TD status does not authorise employment in the United States, and that much is settled. Whether remote work performed in the United States for a foreign employer is treated as U.S. employment is not answered by a simple rule, so it needs advice and a check of current official guidance before anyone relies on it.
Where the honest answer is a question
TD is the dependent status for a TN professional's spouse and unmarried children under twenty-one. A TD dependant may study. A TD dependant may not take employment in the United States, and no length of stay changes that.
The temptation is to reason that a laptop and a Canadian payroll deposit put the work outside the country, and that reasoning is not safe to act on without advice. Hypothetical example: a household leaving Saint-Joachim-de-Shefford has a TN professional and a spouse who books freight for a Québec carrier from her kitchen table. She assumes the arrangement is invisible because the employer, the clients and the bank account are all Canadian.
The honest position is that the question has real analytical content, that the answer can turn on details of the arrangement, and that it should be put to counsel rather than settled by consensus in a group chat. The route that removes the doubt is a status of her own. If she qualifies in her own right for a listed profession, or the household later moves to an L classification where the spouse is employment-authorised, the question disappears rather than being managed.