Hi Roman,
Thanks for the explanation. I hope I got it this time.
That’s the reason I ask you why do you want to deploy the war file separately from the process definition.
You need to deploy the process and related java classes together in one war file and these kind of errors won’t appear. And it seems to me that is the problem in your case.
You should not mix the ways of deployment strategies.
As it is shown in Using Shared Process Engine [1] you project should contain the java logic together with the process under /src/main/resources.
If you download the Source Bonus Code from the bottom of the page [1], you will see that the loanApproval process example is part of the project.
P.S.I think that this post will help you to understand better [2], Niall explained similar scenario. Even that the problem there is that is mixed Rest and war deployment, the point is still the same you should deploy in consistent way.
[1] https://docs.camunda.org/get-started/spring/shared-process-engine/
[2] Exception while starting a new bpmn process instance
Best regards,
Yana