test failure of OpenCL when running on cpu

failure_opencv_test_video_cpu.log

CTEST_FULL_OUTPUT
OpenCV version: 3.4.3-dev
OpenCV VCS version: 3.4.3-306-g11e2a216c
Build type: N/A
WARNING: build value differs from runtime: Release
Compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/x86_amd64/cl.exe  (ver 19.0.24215.1)
Parallel framework: ms-concurrency
CPU features: SSE SSE2 SSE3 *SSE4.1 *SSE4.2 *FP16 *AVX *AVX2
Intel(R) IPP version: ippIP AVX2 (l9) 2017.0.3 (-) Jul 31 2017
OpenCL Platforms: 
    NVIDIA CUDA
        dGPU: GeForce GTX 1060 (OpenCL 1.2 CUDA)
    Intel(R) OpenCL
        iGPU: Intel(R) UHD Graphics 620 (OpenCL 2.1 )
        CPU: Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz (OpenCL 2.1 (Build 10))
Current OpenCL device: 
    Type = CPU
    Name = Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz
    Version = OpenCL 2.1 (Build 10)
    Driver version = 7.2.0.10
    Address bits = 64
    Compute units = 8
    Max work group size = 8192
    Local memory size = 32 KB
    Max memory allocation size = 3 GB 1005 MB 241 KB
    Double support = Yes
    Host unified memory = Yes
    Device extensions:
        cl_khr_icd
        cl_khr_global_int32_base_atomics
        cl_khr_global_int32_extended_atomics
        cl_khr_local_int32_base_atomics
        cl_khr_local_int32_extended_atomics
        cl_khr_byte_addressable_store
        cl_khr_depth_images
        cl_khr_3d_image_writes
        cl_intel_exec_by_local_thread
        cl_khr_spir
        cl_khr_dx9_media_sharing
        cl_intel_dx9_media_sharing
        cl_khr_d3d11_sharing
        cl_khr_gl_sharing
        cl_khr_fp64
        cl_khr_image2d_from_buffer
    Has AMD Blas = No
    Has AMD Fft = No
    Preferred vector width char = 1
    Preferred vector width short = 1
    Preferred vector width int = 1
    Preferred vector width long = 1
    Preferred vector width float = 1
    Preferred vector width double = 1
Note: Google Test filter = OCL_Video*PyrLKOptical*
[==========] Running 8 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 8 tests from OCL_Video/PyrLKOpticalFlow
[ RUN      ] OCL_Video/PyrLKOpticalFlow.Mat/0, where GetParam() = (11, 3)
C:\work\opencv-replace\modules\video\test\ocl\test_optflowpyrlk.cpp(148): error: Expected: (bad_ratio) <= (eps), actual: 0.068 vs 0.03
[  FAILED  ] OCL_Video/PyrLKOpticalFlow.Mat/0, where GetParam() = (11, 3) (162 ms)
[ RUN      ] OCL_Video/PyrLKOpticalFlow.Mat/1, where GetParam() = (11, 5)
C:\work\opencv-replace\modules\video\test\ocl\test_optflowpyrlk.cpp(148): error: Expected: (bad_ratio) <= (eps), actual: 0.07 vs 0.03
[  FAILED  ] OCL_Video/PyrLKOpticalFlow.Mat/1, where GetParam() = (11, 5) (152 ms)
[ RUN      ] OCL_Video/PyrLKOpticalFlow.Mat/2, where GetParam() = (15, 3)
C:\work\opencv-replace\modules\video\test\ocl\test_optflowpyrlk.cpp(149): error: Expected: (err_ratio) <= (erreps), actual: 0.975 vs 0.1
[  FAILED  ] OCL_Video/PyrLKOpticalFlow.Mat/2, where GetParam() = (15, 3) (118 ms)
[ RUN      ] OCL_Video/PyrLKOpticalFlow.Mat/3, where GetParam() = (15, 5)
C:\work\opencv-replace\modules\video\test\ocl\test_optflowpyrlk.cpp(149): error: Expected: (err_ratio) <= (erreps), actual: 0.974 vs 0.1
[  FAILED  ] OCL_Video/PyrLKOpticalFlow.Mat/3, where GetParam() = (15, 5) (152 ms)
[ RUN      ] OCL_Video/PyrLKOpticalFlow.Mat/4, where GetParam() = (21, 3)
[       OK ] OCL_Video/PyrLKOpticalFlow.Mat/4 (115 ms)
[ RUN      ] OCL_Video/PyrLKOpticalFlow.Mat/5, where GetParam() = (21, 5)
[       OK ] OCL_Video/PyrLKOpticalFlow.Mat/5 (143 ms)
[ RUN      ] OCL_Video/PyrLKOpticalFlow.Mat/6, where GetParam() = (25, 3)
[       OK ] OCL_Video/PyrLKOpticalFlow.Mat/6 (33 ms)
[ RUN      ] OCL_Video/PyrLKOpticalFlow.Mat/7, where GetParam() = (25, 5)
[       OK ] OCL_Video/PyrLKOpticalFlow.Mat/7 (33 ms)
[----------] 8 tests from OCL_Video/PyrLKOpticalFlow (908 ms total)

[----------] Global test environment tear-down
[==========] 8 tests from 1 test case ran. (908 ms total)
[  PASSED  ] 4 tests.
[  FAILED  ] 4 tests, listed below:
[  FAILED  ] OCL_Video/PyrLKOpticalFlow.Mat/0, where GetParam() = (11, 3)
[  FAILED  ] OCL_Video/PyrLKOpticalFlow.Mat/1, where GetParam() = (11, 5)
[  FAILED  ] OCL_Video/PyrLKOpticalFlow.Mat/2, where GetParam() = (15, 3)
[  FAILED  ] OCL_Video/PyrLKOpticalFlow.Mat/3, where GetParam() = (15, 5)

 4 FAILED TESTS