The test fails the expectation on line 100 of navigation_egtest.mm. The URL bar did not get updated to include the fragment as expected.

../../ios/web/shell/test/earl_grey/shell_matchers.mm:49: error: -[NavigationTestCase testNavigationBackAndForwardAfterFragmentLink] : Exception: AssertionFailedException
Exception Details: Address field text did not match. expected: http://127.0.0.1:52454/fragmentlink/#hash, actual: http://127.0.0.1:52454/fragmentlink/

The URL of the underlying WKWV is updated. The bug could be in the code that notifies the UI layer to update URL after navigation.