I read you (tks ).
So, yes the quick-edit module can be a workaround.
In my case it will make me to change a little the things so i drop structure feature (not part of the module) and instead use "Category" to generate a listing (kind of menu) with the pages added by all the authorized users.
Could be other issues but seams acceptable.
Of course it doesn't make the bug go away !!
Adding page for a user belonging to a group that has right to create page in category and default category for created object is set (same) should work.