Steps:
1. Build and Run the attached project on Android ("TargetFramerateTests.zip")
2. In device: click "Next VSync" button

Result: player crashes.

Stacktrace (see full in "S20 error.txt"):
2020/05/29 12:07:23.587 31269 31337 Error CRASH backtrace:
2020/05/29 12:07:23.587 31269 31337 Error CRASH #00 pc 00183f40 /vendor/lib/hw/vulkan.kona.so (BuildId: 937baf8506659f6173ac17932cd20a9d)
2020/05/29 12:07:23.587 31269 31337 Error CRASH #01 pc 00148a9d /vendor/lib/hw/vulkan.kona.so (qglinternal::vkCreateFramebuffer(VkDevice_T*, VkFramebufferCreateInfo const*, VkAllocationCallbacks const*, unsigned long long*)+4220) (BuildId: 937baf8506659f6173ac17932cd20a9d)
2020/05/29 12:07:23.587 31269 31337 Error CRASH #02 pc 008fa2d8 /data/app/com.DefaultCompany.TargetFramerateTests-_rKPZSdKFro6u1fi9XyIDw==/lib/arm/libunity.so vk::Framebuffers::BeginUseFramebuffer(vk::CommandBuffer*, RenderPassSetup const&, unsigned long long, bool, int) at ??:?
2020/05/29 12:07:23.587 31269 31337 Error CRASH #03 pc 0090279c /data/app/com.DefaultCompany.TargetFramerateTests-_rKPZSdKFro6u1fi9XyIDw==/lib/arm/libunity.so vk::RenderPassSwitcher::BeginCurrentRenderPass(vk::CommandBuffer*) at ??:?

Reproduced with: 2020.2.0b3, 2018.4.26f1.

Reproducible with devices:
N/A, Xiaomi Mi A3 (Mi A3), Android 9, CPU: Snapdragon 665 SM6125, GPU: Adreno (TM) 610
VLNQA00229, Oneplus OnePlus6T (ONEPLUS A6013), Android 9, CPU: Snapdragon 845 SDM845, GPU: Adreno (TM) 630
VLNQA00277, Asus ROG Phone (ASUS_Z01QD), Android 8.1.0, CPU: Snapdragon 845 SDM845, GPU: Adreno (TM) 630

Not reproducible with devices:
VLNQA00096, Samsung Galaxy S8 (SM-G950F), Android 8.0.0, CPU: Exynos 9 Octa 8895, GPU: Mali-G71
VLNQA00121, Samsung Galaxy S9 (SM-G960F), Android 9, CPU: Exynos 9 Series 9810, GPU: Mali-G72
VLNQA00021, Samsung Galaxy S7 (SM-G930F), Android 8.0.0, CPU: Exynos 8 Octa 8890, GPU: Mali-T880
VLNQA00288, Samsung Galaxy J7 (SM-J730F), Android 8.1.0, CPU: Exynos 7 Octa 7870, GPU: Mali-T830
iPhone (documentation: the VSync setting is ignored)
Windows Standalone
macOS Standalone
Editor

Code:
public void NextVSYNC()
{
if (QualitySettings.vSyncCount < 2)
QualitySettings.vSyncCount++;
else
QualitySettings.vSyncCount = 0;
}