What would cause a dip in EV (Earned Value) (Tempo Budgets)?

Question

I am trying to find the issues that caused the pictured dip to occur and to prove my theories on why it happened. Does anyone have any suggestions? Additionally , here are my theories am I totally incorrect? 
Theory one: Issues moved from a closed state back to an active state, however, those issues are not back to a closed state and the earned is not lined back up. 
Theory two: Story point values were changed after the issue was closed.

Alexander Eck [Tempo] · Answer

No. Not in this case

Ruth Powers_nwhv3q · Answer

So, if I when I started say a state is closed, but then edit configuration later it would cause this dip?

Alexander Eck [Tempo] · Answer

HI Ruth,

it depends of course on your configuration settings. But given the scenario that you have chosen story points as your effort field and you set a non-progressive effort both scenarios could be true. In the non-progressive evaluation you will earn value when an issue gets resolved. Means at the end we could add another third theory: some issue statuses of your scope are no longer considered as resolved.

Hope that helps rather than confuses you.

BR