You have a bit of a misunderstanding but the situation is complicated because it really is a result of mistakes by everyone: Samsung, Apple, and the Judge.
Samsung did bring up their evidence near the end of discovery but they were still in the phase of the trial when such things should be admissible as long as it wasn't intentionally delayed until the end. There is practically a tradition in the legal profession of submitting exhibits and discovery at the last possible moment, and having it ruled inadmissible is one of the risks they take with that and Apple won in saying that the F700 should be inadmissible. That's fine.
Where things go sketchy is that Apple then brought up the F700 design as an example of a Samsung iPhone copy in its opening statements. Samsung argued that by bringing up the F700 Apple opened the door for further information about the device (particuarly that it was in development before the iphone was announced) which is the way things normally work for this sort of situation. The Judge said no. However the Judge also has ruled and issued statements that everything in the trial is to be open, so Samsung pointed to the evidence when asked what the flap was about by a media contact.
The Judge was angry about this, but the Samsung lawyer's response was basically bulletproof and hung the Judge to dry by both her own statements and overwhelming precedent. Apple's lawyers have been very loudly hoping to capitalize on the Judge's unhappiness while (hypocritically IMO) they (or Apple PR) have been feeding the press a steady stream of "Samsung did a horrible thing by speaking to the press!" quotes.
Samsung's legal team made a mistake in not getting the F700 in earlier. Apple's legal team made a mistake in mentioning the F700, and in doing so allowed Samsung's team to immediately tee-up this case for a very strong appeal should they lose. The Judge made a mistake in her very aggressive response to Samsung's media statement and may have strengthened Samsung's appeal case by seeming to not be impartial. The only party seeming to be doing a perfect job is the Jury, which has been following the instructions to avoid all media on the case and thus likely doesn't have a clue about all of this bickering.