The same is happening to me right now. Full restore with the phone set as new. Everything is back at its place and the Other is going up. Now it's 1.6GB but I'm affraid it will be 2.1GB the next time I'll sync the phone.
Just had that happen. Other is now 2.26. It is getting to the point where I am reluctant to even update an app. I have no clue where the growth comes from as I am very careful to clear the cache of any app that has that ability.