ADC12DJ5200RFEVM: SYNC Signal Stability Issue: REV D vs. REV E2 EVM Boards

We are working with both the REV D and REV E2 EVM boards. On the REV E2 board, we are able to capture data successfully, and the SYNC signal is stable. However, on the REV D board, the SYNC signal is not stable, and we sometimes observe SYNC toggling. We are using the onboard clocking option and configuring the device through the ADC_GUI. The sampling rate is 3200 MSPS, and JMOD3 settings are used.