As the title suggests - after upgrading to beta10 (and angular2 rc3) our app seems very unstable. Our Sass styles are not applied to some pages (while others are fine) and the use of nav functions (push, setroot) are not doing what they should, and instead seem to be causing a page that had originally loaded (with sass style) to be reloaded without the style - and if the same nav function is fired a second time, the ion-content is blank. I don’t have any idea where to start. Any help would be appreciated.
Have you gone through the change log to double check your code? Make sure everything has been updated for beta 10
Aside from the addition of the <ion-header> tags around my navbar, there did not seem to be anything else that needed to be done as far as I could tell.
I am having the same issue all nav bars have gone!
I have done :
sudo npm install -g ionic@beta
in my app folder:
npm install ionic-angular@latest
npm update
gulp build
added the around the
can’t work it out 
ok removing *navbar from ion-navbar fixed it for me