We've found an issue we can reproduce fairly reliably with an empty Unity/Vuforia project under iOS 10.

We're using Unity 5.4.2p3 (but have seen it with older versions including 5.3.6) and Vuforia 6.0117. We do not see this on older versions of iOS.

Steps are:

1. Launch the app, turn phone to landscape mode
2. Press the power button to lock the phone while in landscape.
3. Turn to portrait mode and wait 5s before unlocking.
4. Upon return, the screen is frozen with a stretched image (see attachment)
5. Turning the phone to landscape resets and clears the error.

Also, while the stretched image is displayed, the following is dumped to the xcode log every frame:

OPENGL NATIVE PLUG-IN ERROR: GL_INVALID_FRAMEBUFFER_OPERATION: Framebuffer is not complete or incompatible with command
Vuforia.VuforiaRendererImpl:UnityRenderEvent(RenderEvent)
Vuforia.VideoBackgroundAbstractBehaviour:OnPostRender()

[/Users/builduser/buildslave/unity/build/Runtime/GfxDevice/opengles/GfxDeviceGLES.cpp line 265]
(Filename: /Users/builduser/buildslave/unity/build/Runtime/GfxDevice/opengles/GfxDeviceGLES.cpp Line: 265)

OpenGLES error 0x0506 in /Users/Mike/Development/Projects/HoloTats_v2_iOS/Builds/ios/UnderAR_v1.2_b41_dev/Classes/Unity/GlesHelper.mm:339
OPENGL NATIVE PLUG-IN ERROR: GL_INVALID_OPERATION: Operation illegal in current state
Vuforia.VuforiaRendererImpl:UnityRenderEvent(RenderEvent)
Vuforia.VideoBackgroundAbstractBehaviour:RenderOnUpdate()
System.Action:Invoke()
Vuforia.VuforiaAbstractBehaviour:UpdateStatePrivate(Boolean, Boolean)

[/Users/builduser/buildslave/unity/build/Runtime/GfxDevice/opengles/GfxDeviceGLES.cpp line 265]
(Filename: /Users/builduser/buildslave/unity/build/Runtime/GfxDevice/opengles/GfxDeviceGLES.cpp Line: 265)

Any help is greatly appreciated!

-Will