Had the same problem. You need delete the newer version of Wwise from you project and integrate the 2017.1.2 version instead.
Not sure why it does it, had a chat with a staff member and said they will have the integration team look into it.
Hopefully it will get fixed at some point, but the above is the only solution I found and worked for me.
You can test with a blank project if you want be cautious.