rubocop-rspec: RuboCopRSpec not working / no errors reported with RuboCop 0.56

Steps to reproduce:

1. Gemfile:

source 'https://rubygems.org'

gem 'rubocop'
gem 'rubocop-rspec'

1. Create a file called trol_spec.rb in the spec/ dir
2. Bundle
3. Run rubocop-rspec with following command:

bundle exec rubocop --only RSpec --require rubocop-rspec

1. See errors:

[dadad]$ bundle exec rubocop --only RSpec --require rubocop-rspec
Inspecting 2 files
.An error occurred while RSpec/AlignLeftLetBrace cop was inspecting /home/mencio/Pulpit/dadad/spec/trol_spec.rb.
To see the complete backtrace run rubocop -d.
An error occurred while RSpec/AlignRightLetBrace cop was inspecting /home/mencio/Pulpit/dadad/spec/trol_spec.rb.
To see the complete backtrace run rubocop -d.
.

2 files inspected, no offenses detected

2 errors occurred:
An error occurred while RSpec/AlignLeftLetBrace cop was inspecting /home/mencio/Pulpit/dadad/spec/trol_spec.rb.
An error occurred while RSpec/AlignRightLetBrace cop was inspecting /home/mencio/Pulpit/dadad/spec/trol_spec.rb.
Errors are usually caused by RuboCop bugs.
Please, report your problems to RuboCop's issue tracker.
https://github.com/bbatsov/rubocop/issues

Mention the following information in the issue report:
0.56.0 (using Parser 2.5.1.0, running on ruby 2.5.1 x86_64-linux)