REST API error message or return message should be specific

Summary

As a user of Jira's REST API, sometimes, the error message or return message is quite confusing when there are certain permissions used against the project.

It would be good if the error message or return message could be specific in the case when the issue is caused by a permission problem but the return message fails to state the actual problem and gives a generic message. For example, trying to update an issue field on an issue that is blocked due to security level. The API should state that "you do not have permission on this issue" rather than return a 200 okay response.