Ok, so this looks to be an issue with the default osStatusBarHeight for iOS. This has changed in iPhone X XS etc.
It needs to be update in \frameworks\projects\mobiletheme\defaults.css (line 1359) to 90 (if I am converting it correctly) as the new iOS StatusBar Heitght is 44pt -- Sent from: http://apache-flex-development.2333347.n4.nabble.com/
