When changing the Camera's render target to a RenderTexture, regular rendering is invalid. This only occurs on Metal, it works as expected on OpenGLES3

To reproduce:

1. Download projects from attached links and open in Unity
2. Open the Workflow window from the menu "Sago > Workflow"
3. In the Workflow window:
* Set the Mode to "Build Complete"
* Set the Platform to iOS (wait for recompile)
* Optionally, check "Development Build" and "Allow Debugging"
* Set the Build Type to "Device"
* Set the Build Action to "Build and Run"
* Press the "Build Project" button at the bottom
4. Eventually, XCode will launch, at which point you can work normally (e.g. build to the device)
5. Deploy the Xcode project to the iOS device
6. Launch "Hat Maker"
7. Tap to skip the intro screen
8. On the title screen, tap the arrow to begin playing
9. Tap the bell to bring in the character
10. Drag a hat onto the character's head
11. Press the right arrow in the upper right corner of the screen to advance to the next station
12. Continue advancing to the station with the colored circles at the bottom (3 arrow presses total)

Expected results: You should now be able to draw on your hat
Actual results: The screen will turn black

Notes:
- This issue appears only on iOS with Metal
- On Android, this issue does not reproduce
- Project links are attached in Comments section
- The game has not crashed, if you tap the screen where the arrows were, you will change screens and things will return to normal
- It seems that it is related to Devices with SoC <= A8

Reproduced with:
- iPhone 6, iOS: 11.3.1, SoC: A8
- iPad Mini 4, iOS: 11.4.1, SoC: A8
- iPad Mini 2, iOS: 11.4.1, SoC: A7

Not reproduced with:
- iPhone 6s Plus, iOS: 10.3.2, SoC: A9
- iPad Mini, iOS: 8.4.1, SoC: A5
- iPhone 7 Plus, iOS: 12.0, SoC: A10

Crashes on:
- iPhone 6 Plus, iOS: 8.0, SoC: A8

Reproduced on Unity 2017.4.13f1, 2018.1.9f2 and 2018.2.12f1
Could not check on Unity 2018.3 and 2019.1 because of this issue:
https://issuetracker.unity3d.com/issues/ios-blocking-cameracapture-dot-mm-script-causing-static-array-count-error-preventing-testing-with-vuforia
Could not check for Regression because project becomes corrupted and starts crashing