Airflow error importing DAG using plugin - Relationships can only be set between Operators

Question

I have written an airflow plugin that simply contains one custom operator (to support CMEK in BigQuery). I can create a simple DAG with a single task that uses this operator

Answer 1

There was a bug introduced in composer-1.4.2 release which we have fixed by now, try create a new Composer environment and that DAG error should go away. Meanwhile, we'll also apply that fix automatically on existing 1.4.2 environments over the next few days.