Select query failing to return all values

Question

So I've just completed my first batch insert into DocumentDB and ran into the following irregularity while verifying my documents were added correctly.  I am seeing this issue through the Portal Query Explorer and the Python SDK.
I have found 4 id values that are in my collection, but won't get returned in a Select all type query.  
Queries I've used to select just that item/document.  These work correctly and return my document.  Therefore, I assume the document is in the collection.
SELECT * FROM Matches m WHERE m.id = "2997"
SELECT VALUE m.id FROM Matches m WHERE m.id = "2997"
However, when doing a broader SELECT query, some ids are not returned.
SELECT * FROM Matches
SELECT VALUE m.id FROM Matches m
Neither of the above queries return the document with id "2997".  I've three other ids where this is the case.
Am I missing something obvious here, or is there a bug?  I've added all ~991 documents into the collection using the same batch program.
Edit:  Here's a test program I've drawn up to show this issue (you can take my word for it that the clients are initialised correctly):  https://gist.github.com/Fitzpasd/1dde776b00eacf68b361
And this prints:
1
991
False
False
False
True

Answer 1

I also have some issues with pages. When I execute a simple query like:
SELECT x FROM Root x
or 
SELECT s FROM Root x JOIN s IN x.Children
(The Children array contains more than 100 items)
And I use the AsDocumentQuery() method in the c# API, iterating through the pages works fine (the continuation token is returned in the request)
But when I execute the following query:
SELECT s FROM Root x JOIN s IN x.Children WHERE x.id = "<guid>"
the continuation token is not returned so I can't get to the next pages.
Is this related to the same bug ?