🐛 | Coder | On 8.3.14 (but not 8.3.13): ERROR: Referenced sniff "SlevomatCodingStandard.ControlStructures.RequireNullCoalesceOperator" does not exist
Thank you, @geoanders. I downgraded coder (composer global require drupal/coder:8.3.13) and it fixed the issue right away.
#18 worked for me thank you @geoanders