Dual ADC mode with DMA circular mode problem for STM32L475

In the reference manual, it is showing that for the dual-mode circular mode we need to use the DMA related bits in the ADC12_COMMON -> CCR instead of DMA bits in ADC1 -> CFGR.

For me, this DMA transfer in circular mode is working properly only when DMACFG is enabled in ADC1 -> CFGR and ADC2 -> CFGR but not when enable in ADC12_COMMON -> CCR?

I believe there are some bugs in the dual-mode implementation document provided by ST.

Below cases tested, few cases working and few not working.

Any proper example to refer to or procedure to do?

I found that one of the people used the DMAEN in the ADC1->CFGR in dual-mode then only it worked. (adc - STM32 dual regular simultaneous mode with DMA - Electrical Engineering Stack Exchange).