Reproduction steps:
1. Open the attached project ("Test2020LightingBug.zip")
2. Open "SampleScene" scene
3. Enter Play mode

Expected result: No errors thrown in the console
Actual result: ArgumentOutOfRangeException is thrown constantly:

ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
Parameter name: Red color (Infinity) must be in range [0;1].
UnityEngine.Experimental.GlobalIllumination.LinearColor.set_red (System.Single value) (at <fb900ccbd717476f91b221d941550640>:0)
UnityEngine.Experimental.GlobalIllumination.LightmapperUtils.ApplyColorTemperature (UnityEngine.Color cct, UnityEngine.Experimental.GlobalIllumination.LinearColor& lightColor) (at <fb900ccbd717476f91b221d941550640>:0)
UnityEngine.Experimental.GlobalIllumination.LightmapperUtils.Extract (UnityEngine.Light l, UnityEngine.Experimental.GlobalIllumination.DirectionalLight& dir) (at <fb900ccbd717476f91b221d941550640>:0)
UnityEngine.Experimental.GlobalIllumination.Lightmapping+<>c.<.cctor>b__7_0 (UnityEngine.Light[] requests, Unity.Collections.NativeArray`1[T] lightsOutput) (at <fb900ccbd717476f91b221d941550640>:0)
UnityEngine.Experimental.GlobalIllumination.Lightmapping.RequestLights (UnityEngine.Light[] lights, System.IntPtr outLightsPtr, System.Int32 outLightsCount, Unity.Collections.LowLevel.Unsafe.AtomicSafetyHandle safetyHandle) (at <fb900ccbd717476f91b221d941550640>:0)

Reproducible with: 2020.1.0a20, 2020.1.5f1, 2020.2.0b2
Not reproducible with: 2018.4.26f1, 2019.4.10f1, 2020.1.0a19