[nottorp]

> The initialization sequence for the ADC is documented as requiring a wait until the ADRDY flag is set, so the fix is just to wait for that for each ADC in turn before enabling the next one.

Hmm? Ok, it may be the clock or something else subtle but if they tell you to wait...

[jpieper]

In this case, the firmware did wait for the ADRDY flag. It just waited for all 5 to be set, then moved on to enable all 5 ADCs simultaneously. The easy fix was to just do those serially instead.