Perhaps it's just a mistake, but that would be a pretty odd mistake to make. (windowscentral.com)
If the answer is anything other than that it's an odd mistake, then you say, «While your job is specialist, that's the title you need to use in your emails and other places.» (inc.com)
When your business has grown large enough, you must let go the reins, empowering your team to run the company and even to make the odd mistake. (canadianbusiness.com)