To reproduce:

1. Download and open "rotate-test.zip" project.
2. Select "NewUnlitShader" in Assets folder.
3. In the inspector click "Compile and show code" button.
4. In the compiled code notice lines with "Keywords set in this variant" words.

Expected result: Only one multi_compile statement is executed and it outputs:
Keywords set in this variant: A
Keywords set in this variant: B

Actual result: Both multi_compile statements in "NewUnlitShader" shader are executed resulting in wrong results:
Keywords set in this variant: A C
Keywords set in this variant: A D
Keywords set in this variant: B D

Reproduced with: 2017.1.0b6, 5.6.1p1, 5.5.3p2, 5.4.5p1

Notes: multi_compile is surrounded by if/else statement, one multi_compile being in if clause and other multi_compile in else close. Thus both are executed, even thought if/else should limit only one these statements to be executed.