Are you sure those dates are correct? I ordered my P4 within a minute or so when it was posted on DJI's website and it was delivered on April 5th.
The batteries listed as the 342 model are the old batteries. All of the old version batteries are not cracking. It's just a possible issue with the old version batteries. If you want to save a few bucks, get the old version from an authorized DJI dealer -- like
USA Toyz or
The Camera Box. Then, if the battery does by chance crack, you can get it replaced for free through DJI.
DJI is currently selling batteries on
here on their website for $169. If you purchase batteries from the directly, you'll receive the new version.