How to reproduce:
1) Bake any project with GPU lightmapper using a Mac. The following machines are affected, potentially more:
- Mac mini 2018
- MacBook Pro 2017
2)for example https://github.cds.internal.unity3d.com/unity/lighting.denoiser-tests.
3) Observe the following error when it reaches the GPU baker init:

-- GPU Progressive lightmapper will use OpenCL device 'Intel(R) Core(TM) i7-7920HQ CPU @ 3.10GHz' from 'Intel'--
OpenCL Error. Falling back to CPU lightmapper. Error callback from context: [CL_INVALID_KERNEL_ARGS] : OpenCL Error : clEnqueueNDRangeKernel failed: kernel_arg 3 has not yet been initialized
OpenCL Error: 'GetBuffer(kRRBuf_expandedTexelsBuffer).EnqueueClearBuffer(openCLState)' returned -52 (CL_INVALID_KERNEL_ARGS)!

-- GPU Progressive lightmapper will use OpenCL device 'Intel(R) Core(TM) i7-8700B CPU @ 3.20GHz' from 'Intel'--
use -OpenCL-PlatformAndDeviceIndices <platformIdx> <deviceIdx> or -OpenCL-ForceCPU as command line arguments if you want to select a specific adapter for OpenCL.
[00:00:01] Enlighten: Finished 1 Create Input Lighting job (0.00s execute, 0.00s integrate, 0.03s wallclock)
Launching external process: /Users/bokken/.Editor/Unity.app/Contents/Tools/JobProcess
[00:00:01] Enlighten: Finished 1 Bake Runtime job (0.01s execute, 0.00s integrate, 0.02s wallclock)
[00:00:01] Enlighten: Bake took 0.052204 seconds.
[PathTracer] Loaded OpenCL shaders in 4.155 secs -> Timestamps: [212.461 - 216.616].OpenCL Error: 'GetBuffer(kRRBuf_expandedTexelsBuffer).EnqueueClearBuffer(openCLState)' returned -52 (CL_INVALID_KERNEL_ARGS)!
OpenCL Error: 'GetBuffer(kRRBuf_expandedTexelsBuffer).EnqueueClearBuffer(openCLState)' returned -52 (CL_INVALID_KERNEL_ARGS)!
OpenCL Error: 'GetBuffer(kRRBuf_expandedTexelsBuffer).EnqueueClearBuffer(openCLState)' returned -52 (CL_INVALID_KERNEL_ARGS)!
OpenCL Error: 'params.openCLState.intersectWithTransmission.EnqueueNDRangeKernel(params.openCLState, 1, NULL, intersection_global_work_size, intersection_local_work_size, 0, NULL, NULL)' returned -54 (CL_INVALID_WORK_GROUP_SIZE)!

See https://yamato.cds.internal.unity3d.com/jobs/1229-lighting.denoiser.tests/tree/master/.yamato%252Fupm-ci_FAST.yml%2523OSX_Metal_editmode_trunk/4179470/job/artifacts for full test run results.

Expected outcome: GPU bake finishes without errors.