Two things you may want to check:
1) Is session Tracking, Awareness enable? If yes, turn them off.
If then after disabling the above, you still see white page, then check if you application is SPA. If so, then, enable SPA
2) enable SPA:
Security ›› Options : Application Security : Advanced Configuration : System Variables
Look for single_page_application
Enable it
Note: You must perform a 'tmsh restart sys service asm' for this change to take effect! If you are using a device group you must perform 'tmsh restart sys service asm' on all members of the device group for this change to take effect!
If you still see a white page, open a support case.