To reproduce:

1. Download attached project "ContactFilter2D.zip" and open in Unity
2. Open "scene" scene
3. Enter to Play mode

Expected result: In Console window, these messages will start spamming:

useNormalAngle = false: Hit!! Angle = 90
IsFilteringNormalAngle(90) = False
useNormalAngle = true: Hit!! Angle = 90

Actual result: In Console window, only these messages will start spamming:

useNormalAngle = false: Hit!! Angle = 90
IsFilteringNormalAngle(90) = False

And this message will appear only one time:

useNormalAngle = true: Hit!! Angle = 90

Note: This issue appears only on OSX.

Reproduced on Unity 5.6.0p1, 5.6.1p1, 2017.1.0b7 and 2017.2.0a1