I have set ADC_ACCESS_MODE_STREAMING Access Mode, ADC_DMA. Adc Group Enable Double Buffering can not be selected.
Not sure if you have found out the solution, but you can refer to: 3.6.4.3 Enable Double Buffering Optimization chapter in AUTOSAR_MCAL_ADC_UM.pdf (ASR_4.2_RTM_1.0.4 version).
Best Regards,
Nam