Test suite order dependent ONLY on CI

My test suite was failing intermittently on CI, but never locally. I updated my circle.yml file to include the randomized seed in an attempt to replicate locally.


    - bundle exec rspec --order random

After finding a failing seed number I ran locally with that failing seed many times to rule out timing failures, but local runs never have any failures using the following command:
rspec --seed 29069

Any ideas what could cause order failures ONLY on CI?