There is a BUG in the GUI when entering an event and adding an artist with vocal AND instrument attributes at the same time, for example:
The artist shows up 2 times in the Relationship window (actually I already edited the first entry and added “electric guitar” to “lead vocals” and already deleted the second double entry, but it needs votes, but I think you get the idea) :
The corresponding event also shows up 2 times in the event page: