They have no choice but to add every possible currently known issue *now* or lose the right to ever raise them. That's the way the US system works. While I suspect the Seagate issue is imaginary only 1 man knows for sure. His real reasons for corrupting the jury process may never be known.
What's important to remember is today's report is only about Koh responding to recent filings, over this specific issue and the more dangerous 'when did Apple know' question. Hogan's reported behaviour in the jury room is already part of the proceedings and will be handled in the same Dec6 hearing.
If Koh doesn't void the result there are so many procedural errors in the jury verdict it's unlikely to stand anyway. In fact if Apple cared about collecting the $1bil they would be trying to rehear the case, the verdict wording prevents them collecting triple damages! They don't because they actually only want the bad Samsung PR and to prolong the legal harassment, a 2nd trial with a fair jury, with Samsung allowed to present all the evidence, with so many opposing precedents accumulated round the globe isn't likely to go well for Apple.