I have a similar problem in an app of mine that may be related to this problem.
1. When the app starts 100%x = 600 and 100%y = 951 (which is ok).
2. Then the device goes to sleep mode. When it wakes, this device has an unlock screen, which is fullscreen.
3. before unlocking, I turn the screen to landscape
4. I turn it back to portrait
5. I unlock. After it is unlocked and shows my app again, the values of 100%x = 600 and 100%y = 999 (Which are the fullscreen values 951 + 48 for the bar).
They stay those values and are never updated back to 600 and 951 unless the app is closed.
Because of the orientation switch, the code of activity_create has been called again, if this may be of any help.
B4A 2.70
Galaxy Tab 2 7 Inch
Android 4.1.1