On the controller:

users_pair = User.find(@event.proposals.pluck('user_id')).map { |u| [u.id, u] }
@users = Hash[users_pair]

note that the users list is only for who sent proposals for the event.
User.find(@event.proposals.pluck('user_id'))

Then, if the owner dont sent proposals he doesnt have your id in this @users variable.
I added the proposal factory on controller spec to broken and explain this behavior.