Recently rewatched "Before and After". Let's recap.
Kes warns Janeway that eleven months from now they're going to meet a species called the Krenim that will wreak havoc. Leaving aside the Temporal Prime Directive implications, Janeway welcomes full knowledge of their future.
Kes leaves the ship, and sends them 10 years closer to home.
They still run into the Krenim (in fact, they spend two episodes running into the Krenim). Anyone?
My friend at work tells me that the Krenim were expanding their space with their timeship thingy but ten thousand light years seems like a stretch for that to apply.