burnup and burndown charts take the last known value for story points, if that field is set to 0 or cleared

Issue Summary

If you clear or add 0 to the story points of an issue, regardless if you do it within the sprint or first remove the issue from the sprint and add it back, charts will pick up the last known value.

• if you want to reduce the work scope on a burnup chart, it is not enough to change the story points to 0 or clear that field. You have to remove the issue from the sprint.
• if you remove an issue from a sprint and clear or set to 0 the story points and add it back to the sprint, charts will pick up the last known value again.

I tested the situation with burnup chart, but most probably burn down is affected too.

Steps to Reproduce

1. Set up a sprint with some issues having story points
2. change the story points of an issue to 0 or just clear that field
3. remove an issue from the sprint, change the story point to 0 or clear that field, add the issue back to the sprint

Expected Results

Burnup chart is consistent with the changes

Actual Results

If story points is set to 0 or cleared, burn up chart picks up the last known value of the issue

Workaround

Currently there is no known workaround for this behaviour. A workaround will be added here when available.