of course a patent defendant can appeal (and almost certainly will) after a remanded trial has left them with an unfavorable verdict/judgement
in the specific case you mention, the recent trial involved issues that were not even part of the original trial (and subsequent CAFC remand) because it was partially combined with new patent infringement claims not even brought up before that trial was docketed years ago
secondly, even if a new/remanded trial only involved a prior judgment that was remanded, it could still be appealed because there are a slew of new matters where the law may or may not have been applied correctly at trial