How to reproduce:
1. Open attached Unity project
2. Load scene "SampleScene"
3. Enter the Play mode
4. Notice Assertion failure in the Console window

Expected result: Converted 'b' value is 168. Assertion failure should not appear.
Actual result: Value before converting is 168. After converting to HSV and then back to RGB it changes to 167.

Reproduce with: 2019.2.0a10, 2019.1.0b10, 2018.3.12f1, 2017.4.25f1.

Notes:
This issue occurs with some specific values:
RGBA(0, 255, 168, 255): b value is converted to 167
RGBA(0, 168, 255, 255): g value is converted to 167
RGBA(0, 255, 169, 255): b value is converted to 168

Converting works properly with these values:
RGBA(0, 255, 167, 255)
RGBA(0, 167, 167, 255)
RGBA(0, 168, 168, 255)
RGBA(255, 168, 0, 255)
RGBA(0, 255, 170, 255)