mountindex broken (3.1.x)

Since the upgrade to 3.1.3 (and then 3.1.4) I cannot mount an index anymore:

• Create an index in mayan
• Check if index works in WEB UI (OK)
• Use mountindex index_slug /dir to mount the index
• When I list the files in /dir:

1. The system throws an error "Bad address" and all uid/gid/chmod information is "?????"
2. The output traceback of the mountindex program is:

Traceback (most recent call last): File "/opt/mayan-edms/lib/python2.7/site-packages/fuse.py", line 495, in _wrapper return func(*args, **kwargs) or 0 File "/opt/mayan-edms/lib/python2.7/site-packages/fuse.py", line 511, in getattr return self.fgetattr(path, buf, None) File "/opt/mayan-edms/lib/python2.7/site-packages/fuse.py", line 759, in fgetattr attrs = self.operations('getattr', self._decode_optional_path(path), fh) File "/opt/mayan-edms/lib/python2.7/site-packages/fuse.py", line 800, in __call__ return getattr(self, op)(*args) File "/opt/mayan-edms/lib/python2.7/site-packages/mayan/apps/mirroring/management/commands/mountindex.py", line 137, in getattr result = self._path_to_node(path=path, directory_only=False) File "/opt/mayan-edms/lib/python2.7/site-packages/mayan/apps/mirroring/management/commands/mountindex.py", line 73, in _path_to_node node = node.children.get(value=part) AttributeError: 'IndexInstanceNode' object has no attribute 'children'