Steps to reproduce:
1) Download attached project and open in Unity
2) Open "SampleScene"
3) Generate Lighting in the Lighting tab
4) In the player settings, select Lightmap Encoding Quality to High Quality
Note: Lightmap with reflection probes will be encoded for High Quality
5) Select Lightmap Encoding Quality to High Quality again
Note: reflection probes will be recompiled again

Expected result: Reflection probes should not be recompiled if the same setting is selected again
Actual result: Reflection probes are recompiled again (check attached video "repro.mp4")

Reproduced with:
2018.1.9f1, .2018.2.2f1, 2018.3.0a6

Notes:
- Tested using Windows 10 and MacOS machines

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Fixed in: 2018.3.0b1