Failed to return attached pipeline contexts

Overview

Initializing Process step fails with following output:

Error: Failed to prepare variables; 
caused by Error: Failed to return attached pipeline contexts; 
caused by Error: Failed to get context <context-name> with error: 
500 - {"message":"Error: Context <context-name> not found."}; 
caused by [object Object]  

Details

This context being referenced by the pipeline has been deleted, but the reference itself was not removed.

1. Create a dummy shared context with the same name as the missing context from the error message.
2. This dummy context should show up in the pipeline UI. Delete it in the workflow definition -> variables -> advanced options.
3. Delete the dummy shared context.