A planter will only go up to 10 blocks away from his station to plant a sapling.
When I set a work area further away the planter does not move.
When the work area overlaps the maximum range it will only plant up to 10 blocks away from the station.

I'm not sure if this is a bug or intended.

Seems the lumberjack have the same behavior. But since it recalculates target from the last chopped down tree not that obvious.

The picker did move far from his station when needed.