I haven't had this issue.
But, as with anything that is manufactured there are going to be anomalies in some parts. Since the aluminum plate is metal it really shouldn't be an issue to re-form it by applying a bit of force with a bottle jack (hydraulic). If you know of anyone with a press or have one yourself then just push the center down until you have it flat. Why wait for a replacement part? 3d printers have always required a certain amount of DIY. Lots of cheap bottle jacks out there.