If you will have one application only with the webapp part, without the java delegates classes, you need to disable the job executor from it, so it stops to get jobs at database. You need to set Async after in your User task too, so when you complete a task by Tasklist, it will create a new job in database, and let the other project that still has the job executor active and the correct java classes will handle it.
If you let your application with default settings, the job acquisition is enabled by default. So it will take jobs from database and try to execute the javaclasses, wich doesnt exist in this class path, right? the same will happen when you try to complete a user task without Async After, coz it will try to run the next steps within same Database Transaction, in the same java application, wich doesnt have the classes nedded.
Try it setting this property in your bootstrap.yml of the only webapplication java project:
camunda:
bpm:
job-execution:
enabled: false
And dont forget to set async after on your user tasks:
