The Burn down chart was showing the starting point of Guideline correctly for 3 Sprints but for the last 2 Sprints the starting point of burn down isn't correct.
When I closed the previous Sprint, the spillover tickets were moved to new Sprint and then I started the new Sprint but the burn is showing those tickets as scope change.
In the second screenshot below, the Guideline should start from 59 Story Points instead of 37 Story Points. The spillover story points got added after starting the Sprint instead of right when the Sprint was started.