Using buses in multisheet
Repeat() currently doesn't support buses or harnesses in Altium.  Supposedly that feature is in development (https://bugcrunch.live.altium.com/#Idea/2831).  

Your best option at the moment is to place two of your ADC blocks on your main sheet (without using the repeat command).  You could also break out the bus into individual ports and still use the repeat command, but then you wind up with 12 buses with two nets each, which I wouldn't call an improvement.

As an aside, given the number of connections you need to make for each ADC, you may want to use harnesses to consolidate many signals into a single port.