This issue has been closed as 'Won't Fix' due to an extended period of time without updates. If this issue is important to you please let us know by posting on the AnswerHub or UDN, and Epic will re-open the ticket for further review.
When cancelling a build from Visual Studio, UBT keeps running, and another build is generally not possible until one kills the UBT process manually in Task Manager.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-22819 in the post.