Repeatedly seeing the theory around twitter that this was leaked by someone connected to Alito and it does actually make sense. You release some early draft that will have the left on fire for a few months saying that the decision is ultra-radical (which it is) and at the last moment when the actual opinion is released in June/July it is "only" the watered down 15 week ban. Then the Fox News crowd get to go back to their "see, the libs were hysterical again, this isn't an extreme decision" shtick.
They know how horrendous is would look to have the conservative Chief Justice joining the liberals in dissent. So by going instead to the 15 week ban they can get him onboard for the better optics.