Are you using CS 1.1.1? I just tried to reproduce this, and i cannot.
Can you tell me what permissions you have set explicitly, so I can try to reproduce this?
Right now, I see the structure fine, and if i click on B, i receive an 'Unauthorized' page.
I think I may have confused two bugs.
Bug one: Entire tree disappears if content type isn't present in parent.
A = no forum threads, no wiki documents, yes blog posts
A1 = yes forum threads, yes wiki documents, yes blog posts
A1a = yes forum threads, yes wiki documents, yes blog posts
Browse > Discussions
What I expected:
A, A1, A1a appear in the list (the whole tree!) Perhaps A is not a link, since it can't contain discussions?
What I saw:
A, A1, A1a all do not appear in the "Forums"
However, all posts from sub-communities do appear in the roll-up below.
Bug two: Missing parent leaves orphan spaces in New content page.
New > Discussion has a select pop-up to pick the Community.
Because Community A has no discussions, it is missing from the select. However, this leaves A1,A1a are orphaned there and potentially appearing to be from another community.
Version: CSX 1.1.2, but it says "sub-spaces", not "sub-communities", so maybe we upgraded to CS 1.1.2.