Here the description of error is matching with text from hevc spec "The variable Log2MinTrafoSize is set equal to log2_min_transform_block_size_minus2 + 2. The bitstream shall not contain data that result in Log2MinTrafoSize greater than or equal to MinCbLog2SizeY"

The following code snippet from \source\App\TAppEncoder\TAppEncCfg.cpp

xConfirmPara( ( 1 << m_uiQuadtreeTULog2MinSize ) > ( m_uiMaxCUWidth >> m_uiMaxCUDepth ), "Minimum CU width must be greater than minimum transform size." );
xConfirmPara( ( 1 << m_uiQuadtreeTULog2MinSize ) > ( m_uiMaxCUHeight >> m_uiMaxCUDepth ), "Minimum CU height must be greater than minimum transform size." );

these checks are failing when Minimum CU width/Minimum CU height and minimum transform size are both equal.