If you using Track() for your queries you can notice that it sends empty siteid tag:
That happens due to the fact that track request is executed in a separte thread from thread pool where HttpContext.Current is null and CmsSiteIdentityLoader->SiteDefition.Current can't resolve current site.
Suppose that is a bug.
I have entered this into our bug system to make sure it is triaged and investigated.
Thank you for your reporting this!
Just adding the bug # here:Bug #114702: Track() sends invalid (empty) siteid tag