You should have gotten some reminders for this during the game, but you might have missed those. Anyway, in chapter 3 you must also report what you learned about your uncle to your family (they live in a village near Rahib) and Alpharius. You should check the quest "Blood Ties" in the questlog, basically.
Viewing post in Caliross, The Shapeshifter's Legacy comments
So, just to recap: You completed blood ties, and you also completed the temple in chapter 3, correct?
Did you exit on the world map recently? If you got the human/sapient transformation from the temple, and you completed the "blood ties" quest, you should have gotten a message when entering the world map (it's the usual reminder to go visit your uncle's desk to start a new chapter).
I *think* it's possible to complete blood ties without exiting on the world map if you talk to Alpharius last, and that would stop the reminder from triggering until you go on the world map again, which is necessary for the option to advance the chapter to become available.
If this isn't the case, you might want to upload the savefile on a site like MEGA, so I can take a look at it, and figure out what's wrong.