New changes in FLinearColor break compatibility and create non-name-specific functionality.
GetLinearColorValue()
This now returns HSV adjusted value instead of what the function name says. This also means that negative values in the curve asset are now not supported.
New(?) GetUnadjustedLinearColorValue() returns the actual linear color value. This function is also not exposed to BP.
Suggestion : Revert changes so the GetLinearColorValue works as it states, and a new function GetHSVAdjustedValue() that returns the adjusted color.