Hm well I just checked the angularfire2.read.me and all of my packages are up to date.
It even says I have the right version of node and npm
$ node -v
v6.10.2
$ npm -v
3.10.10
I just find it odd that I have no problem when I build and serve the ionic app locally. But for some reason it fails when pushing to ionic pro and the build in the cloud fails.