The solution mentioned in the question did not help me, however it did point me in the right direction.
After some investigation I would say it’s some sort of race condition between presenting and removing the popover. As a workaround you can postpone the presentation in the delegate of the UIWebView:
-(void)presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)flag completion:(void (^)(void))completion
{
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_USEC), dispatch_get_main_queue(),
^{
[super presentViewController:viewControllerToPresent animated:flag completion:completion];
});
}