Taxonomy term: "The requested page "xx" could not be found." In a taxonomy vocabulary, I have terms such as: groups/arts (parent level.)

The URL alias of the term is set as groups/arts (Organic Groups.)

But when I want to access the page www.example.com/groups/arts, I get a "The requested page "/groups/arts" could not be found" error message. This is true regardless of pathauto being enabled or not.

If instead of writing the url I click on the view tab of the taxonomy term edit page (which should bring me to the page) I am sent instead to the root directory (www.example.com)

This issue started after I began using the default view provided for taxonomy. I used the view for for a different vocabulary that works well (the terms have their own pages that show.) However, if I disable the view then I get the same no page found result.

Is it possible that the taxonomy view messed up? Or can one not use it twice on the same site for different vocabularies?

Any pointer on those issues greatly appreciated. Thanks. :) 

Any idea on how to fix this? Is it a .htaccess file issue? If I knew where to start looking that would already be a big help. Thank you. :)
I will answer my own question on this one:

On a site that has several vocabularies, enabling the selection of one of those vocabularies in the contextual filer of the default taxonomy view, removes the paths assigned to the terms of other vocabularies (those that have nothing to do with the view.) Those paths then default to the root directory and the term pages can no longer be found (or used in another view, etc.)

Un-selecting the vocabulary returns functionality to the term paths of other vocabularies but also allows the existing view to be displayed on all vocabulary term pages (this appears to be functioning as designed however.)

It appears to be a bug in the taxonomy module for which there is no fix. :(