Why Team Velocity Report and Query does not match?

We need information on how Team Velocity report is calculated. We committed user stories on first day of iteration, then several user stories were removed later in the iteration. When we ran a query to see user story point delivered per iteration; the result is different than Team Velocity report. The query provides accurate information.

I read a question from another person the "scenario" seems to be the same, how ever in her case the solution was related to fixing an user introduced error on the Project Configuration Source, the complexity enumeration for an OOTB Scrum project... I tried to check the values using the web client and it looks like we have the OOB values... Any ideas?

Thank You