BuddyPress Docs is a great and popular plugin for wiki contents. BuddyPress Group Hierarchy plugin is also a great and popular plugin for hierarchical group structure. Bud they can't work well together.
If I entered a sub level group and activate the Docs feature, when I create a new doc, the URL will be ended with this:
With such URL, the doc can be created successfully. But I recomment to change the URL to below:
Because the hierarchy structure is not added to the URL necessarily. And there are also some minor interface differences between them.
I think the change is easy, please think about it.