Using OnRenderImage and Screen.SetResolution to lower the resolution on OpenGL ES 2.0 on iOS works fine, but if you then try to bring the resolution back to native, it makes the output of the camera with the OnRenderImage turn black.

It doesn't happen 100% of the time, but it happens 80% of the time. Bringing the resolution back down again makes it work again. Also sometimes, it also happens on lower resolutions, more often on an iPad 4 in our tests.

It happens only on OpenGL ES 2.0. If you build with Metal (on a device that supports it), it works fine. We tested on an iPad 4 and an iPhone 6s Plus, we could recreate it on both devices.

Steps:
1. Open attached project ("SetResolution.zip")
2. Build and Run for iOS device
3. On the device, tap the two UI buttons to lower and raise the resolution

Result: You start at native resolution and it should work fine, but as you lower resolution and then raise it back to native (I suggest doing two taps on Lower Resolution and then two taps on Raise Resolution), the screen will turn black (actually, only just the camera with the OnRenderImage turns black, the UI elements should still be visible).

Reproduced with: 2017.3.0b3, 2017.1.2p1, 5.5.5p1.

Tested with: iPad mini 4 iOS9.2.1, Xcode 9.0.

Note: not reproducible on Android and Standalone.