There is IRS guidance for how taxpayers should handle a break between the end of one temporary work assignment and the start of another. 

A Chief Counsel Advice observes that there is no general IRS guidance on how significant a break must be, following a period of temporary employment, for a reassignment to a different work location to be treated as a separate period of work employment that will “restart the clock” on the 1-year limit. The Advice says, however, that a break exceeding 1-year is “clearly significant enough” to restart the clock when the taxpayer begins a 7-month reassignment. (Chief Counsel Advice 200018052, Scenario 7)