[I strongly suspect that it's a duplicate, but Jira's search for "set list", "setlist", "event set list" or a dozen of similar queries returns nothing that makes sense, so I'll report it here anyway]

Setting "setlist" field when editing "event" seems to be totally broken right now and trying to set anything non-empty there seems to trigger validation error "Please ensure all lines start with @, * or #." that blocks submission of edit.

Namely, I've tried to add a set list for this event: http://musicbrainz.org/event/6c4a4b79-e85f-417e-9899-b01b6d43c05a

The field doesn't seem to accept event a single starting line like:

@[3e0c87ae-f6eb-46a4-8c8a-4677280a7884|Сергей Маврин]

or even

@Сергей Маврин

while, as for me, it seems a perfectly valid set list that contains 1 line that starts with "@".