A lot of time travel stories act like there's hard limits that keep characters in sync. With or without reasons for the time travel to work like that.
Internal reasons, that is. External reasons are easy. Trying to interweave character time lines that go back and forth is interesting. And I'm only reworking two scenes to make them in a different order for different characters.
On the other hand, I don't want the point of view character to twig to the difference. Having her confused by what he says adds to the plot.