1) I have the hello world process of the figure 2) I create a process instance of the hello world process by using the Open API UI 3) At the data index we can see that the process was created successfully and that both the priority and description have null values, which is correct. 4) By using the OpenAPI UI I will execute the "claim" operation. Note that the empty json {} is passed as payload. (aside note: if no value is passed a NPE is thrown) 5) The claim operation in step 4) was executed successfully. But now at the data index level we can see that both the priority and the description has the empty string "" as value. That's the bug, in the middle of the execution, don't know exactly if the runtime or at the data index side the empty string was added.