To be brutally honest, I'm fairly involved in the AoS circles (well, I'm on this forum at least!) and I'd struggle to spot new Stormcasts from old.
It's also entirely possible that they cast the skaven models first. It's also entirely possible that these small mistakes just happen to have both been skaven sprues. Packing the wrong sprues into the wrong boxes aren't common. It's actually kind of wild we've gotten 2 for this release.
The Rumour Thread
in Age of Sigmar Discussions
Posted
It's also entirely possible that they cast the skaven models first. It's also entirely possible that these small mistakes just happen to have both been skaven sprues. Packing the wrong sprues into the wrong boxes aren't common. It's actually kind of wild we've gotten 2 for this release.