It depends on how stiff your part of the power grid is. I get the same problem with my large motors because I'm one of 3 houses fed from a small transformer. It can handle the normal running load fine, but the only way that it can deal with the high current draw is by sacrificing the voltage. Once the starting surge is gone and the current drops to steady-state, the voltage can come back up again to where it belongs.
It's REALLY noticable if you have a small emergency generator and only sized it for running loads, not starting loads. You can actually dog the generator down to the point where it dies if you get the sizing wrong enough.
