I found that if I use my pgkk shell function, and kill all spring instances, and then run a test in RubyMine, starting Spring, and then run whatever shell stuff in the console, all is fine with running tests from RubyMine that leverage Spring!
That was my experience as well (I put my findings in the blog article you linked earlier). Whenever it’s complaining about the Teamcity formatter, it means it’s talking to a Rspec process that wasn’t launched from RubyMine - and Spring is generally the culprit. Find and kill any Spring processes, then press “run test” again.