As discussed here

Hello everyone,

When calling User Tasks in an ad-hoc sub-process, the following steps are required:

1. POST /{processName}/{processId}/{taskName} to activate/start the User Task. This returns the taskId, which is needed to complete the started User Task
2. POST /{processName}/{processId}/{taskName}/{taskId} to complete the started User Task

In my reproducer (Ad-hoc-process.zip) this would be:

1. POST /ResolveSupportIssue/{processId}/WriteReplyToCustomer
2. POST /ResolveSupportIssue/{processId}/WriteReplyToCustomer/{taskId}

But Step (1) always returns HTTP 404 NOT FOUND.

This could be a bug. The Task API is not working in ad-hoc processes.