iPad version flashing login details before showing the lock screen

Turning on "Lock When Inactive" will resolve this (Settings > Security > Auto-Lock).

The issue is that with a time-based auto-lock the app can get sent to the background but cannot lock while it is in the background even if the timeout period has elapsed. No code is allowed to execute while it is in the background. Only once it is brought back to the foreground (opened, switched back to, etc.) can it then calculate the lock timeout and perform the lock. This takes a perceptible moment to happen.

"Lock When Inactive" gets around this by simply locking the app before it gets sent to the background. The lock is performed as it it being sent to the background.

We will see how we can improve this in a future update.

Cheers!