Velocity Chart data changes with the board filter

Current Behaviour

When completing a sprint, it's values are updated on the Velocity Chart report. If the board's filter is changed to something that does not include any of the tickets of said report result, they are completely removed from the report. See screen shots for example.

Steps to reproduce:

• Create a board
• Create a few tickets with Estimation
• Put those tickets on the sprint and start it
• Complete a few issues and complete the sprint
• Check the Velocity Chart report. It contains the information regarding the Commitment and Completed values for the Sprint closed
• Change the board filter to filter out some of the issues included on the sprint (I created them with different issue types in order to make the filtering easier)
• Check back the Velocity Chart report and noticed that the initial report data changed.

Expected Behaviour

Reports data consistency is kept and the reports result do not change even after changing the filter board.