Questions regarding WSC round 8 (TEAM) - Clueless

[Richard]

regarding the consecutive circles sudoku. I believe that the rule is "digits on EACH grey circle are all different",in fact there are two circles with the same digits 6789.
I also notice that all possible sets of digits are used (1234,2345,3456 etc.) with one set used twice. Is there any requirement in this respect or is it just a  coincidence?
Also. are all the possible circles marked?

We will add the word EACH to the instructions.
That will be coincidence.
Not all possible circles are marked. In that case it would have been in the instructions.