Unfortunately, iOS 6.1 has not brought a solution to the problem of GWT applications running on Safari Mobile.
This is related to the ClassCastException issue described in the previous article.
Tests done on iOS 6.1 simulator (available from XCode 4.6 Developer Preview). On the OS X version of Safari (6.0.2) the problem doesn't occur.
It is very possible the problem applies to all applications based on AJAX / HTML5 not only GWT.
It is interesting that when the iPad simulator 6.1 (as well as "physical" iPad 6.0.1) is connected to the Remote Web Inspector - all the problems disappear. This may mean that the cause is the optimizer used iOS6 Mobile Safari.
Solution: Compile the application with the -XdisableCastChecking gives a positive result, but I'm afraid other surprises with the new Safari Mobile.
Has anyone experienced similar problems and found a different solution?