Steps to reproduce:

1) Download attached project 'HDRtoLDR_NosRGB.zip' and open in Unity
2) In Player Settings, make sure Color Space is set to Linear
3) Open scene 'asdf' and press Play
4) Observe Console:
'HdrToLdrImageEffect target being sRGB = false' will be spawn in the Console window

Expected result: 'HdrToLdrImageEffect target being sRGB = ' should return true, because HDR to LDR image effect should have sRGB enabled
Actual result: 'HdrToLdrImageEffect target being sRGB = ' returns false

Reproduced with:
5.6.0b11, 5.6.1p1, 2017.1.0b6

Not reproduced with:
5.5.3p3, 5.6.0b10

Regression since:
5.6.0b11

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Fixed in: 5.6.2p3, 2017.1.0p3, 2017.3.0a2