Have a look at this.
When I try to navigate from a new root page
back to a tabbed page the navigation bar flickers. So far, I am using this method to set a new rootPage when in a tabbed page:
this.nav.setRoot(page.pageName, params).catch((err: any) => {
console.log(`Didn't set nav root: ${err}`);
});
This is the Stackoverflow question.