How do I fix the bug? She's not in the training ground and I can't progress with Sakura
Sorry dude I typed a reply when you first asked but somehow managed to delete it without sending. To get Hinata's second night you need the Shadow Clone Jutstu you can get it from speaking to Naruto after enough time has passed, you also need to have completed the infiltration mission to recover a scroll from the mansion in the area. If you've done the mission and waited a while you may still need to progress with the girls I'm afraid I don't know the exact triggers to unlock the Jutsu though it was something that held me up for a while too. Also if you still haven't progressed Sarada's quest this may also be the solution.