Steps to reproduce:

1) Download attached project '56f3AAIssue.zip' and open in Unity
2) Create OSIG file for testing device
3) Enable Gear VR Developer Mode
Settings >> Applications >> Application manager >> Gear VR Service >> Storage >> Manage Storage >> Developer Mode
4) Build and run 'AATest' scene on a device
5) Touch the screen to change AA level
Note: Look at the screen, AA level will not change after pressing on it

Reproduced with:
5.6.0f2, 5.6.0f3, 2017.0b1

Not reproduced with:
5.5.3p1, 5.6.0f1

Regression from:
5.6.0f2

DUT:

Samsung SM G925F (Galaxy S6 Edge), OS:6.0.1, CPU:arm64-v8a, GPU:Mali-T760, Build:samsung/zeroltexx/zerolte:6.0.1/MMB29K/G925FXXU5DQA7:user/release-keys

Note:
Works fine if Virtual Reality Supported is disabled

Fixed in : 5.6.1p3