error message :an item with the same key has already been added

We have just started testing our new installation of 16.7.56.7.

when using the Director client, I am getting the error message "an item with the same key has already been added"  at several different places, but then action is completed

such as - show all attributes, create new from template, copy existing

Is this a problem with our installation? If so how do we fix it?

Thanks