Guard + Zeus + RSpec: RSpec triggered before zeus load the changes

Question

After running zeus start and bundle exec guard, rspec is triggered immediately when I save a file guard is watching. At that point zeus is still reloading the file. Therefore, I have to save the file a second time for the changes to be reflected by rspec. I think it may have something to do with Guardfile:

group :models do
    guard :rspec, cmd: 'zeus rspec' do
        watch('spec/spec_helper.rb')                        { "spec" }
        watch(%r{^spec/models/.+_spec\.rb$})
        watch(%r{^app/models/(.+)\.rb$})                           { |m| "spec/models/#{m[1]}_spec.rb" }
    end
end

How do I track/solve this problem?