Steps to reproduce:
1. Open new project
2. Add a "Raw Image" UI object and a separate Button object to enable/disable the "Raw Image" game object on click
3. Create and assign a new Render Texture to "Raw Image" object
4. Build and Run on Android Vulkan API
5. Clicking the button will cause Button text to appear and disappear even though it's not supposed to affect it at all

Expected: UI shouldn't flicker / disappear when loading render texture objects
Actual: Labels and Button text disappears when enabling / disabling Render Texture raw image in Hierarchy

Reproduced on:
Version 2019.1.0a12 (8459c3aa6e20)
Fri, 30 Nov 2018 20:45:07 GMT
Branch: platform/android/vulkan-video-player

Version 2018.3.0f2 (6e9a27477296)
Sat, 08 Dec 2018 23:47:08 GMT
Branch: 2018.3/release

Devices Under Test:
VLNQA00129, Nvidia SHIELD Tablet (SHIELD Tablet), Android 6.0.1, CPU: nVIDIA Tegra K1 T124, GPU: NVIDIA Tegra
VLNQA00093, Samsung Galaxy S6 edge (SM-G925F), Android 7.0, CPU: Exynos 7 Octa 7420, GPU: Mali-T760
VLNQA00003, Razer Razer Phone (Phone), Android 7.1.1, CPU: Snapdragon 835 MSM8998, GPU: Adreno (TM) 540
VLNQA00125, Google Pixel 2 (Pixel 2), Android 8.1.0, CPU: Snapdragon 835 MSM8998, GPU: Adreno (TM) 540
VLNQA00138, Huawei P20 Pro (CLT-L29), Android 8.1.0, CPU: HiSilicon Kirin 970, GPU: Mali-G72