Summary

If multiple transitions happen in same second, burndown chart will treat them all as a single transition with mix of "from" and "to" statuses from "component" transactions.

This transition's "from" status will be one of "from" statuses of "component" transitions selected from column most to the right possible.

This transition's "to" status will be one of "to" statuses of "component" transitions selected from column most to the right possible.

Both "from" and "to" statuses can be picked from different "component" transisions.

This means that in some cases transition from "To do"/"In progress" to "Done" can be missed and not shown on burndown chart.

Example:

2 columns on board:

1. Column 1 statuses:
   1. To do
2. Column 2 statuses:
   1. Done
   2. Released 

Transitioning issue: "To do" -> "Done" -> "Released"
Can be treated by burndown chart as single transition: "Done" -> "Released"

Steps to reproduce

Import dataset:

burndown-chart-in-one-sec.zip (exported from Jira 7.2.0; user: admin/admin)
Access boards under:

1. <Jira>/secure/RapidBoard.jspa?rapidView=1&view=reporting&chart=burndownChart&sprint=1
2. <Jira>/secure/RapidBoard.jspa?rapidView=2&view=reporting&chart=burndownChart&sprint=1

OR

Setup from vanilla instance:

1. Create project with 2 scrum boards based on it.
2. Add "Released" status and assign it to "Done" column for both boards.
3. Assign "Done" status to "In progress" column only for 1st board.
4. For the project
   1. Create sprint.
   2. Add one issue to it.
   3. Estimate the issue.
   4. Start the sprint.
5. Make 2 transitions of the issue to "Done" and "Released" in a single second.
   • You can use JVM debugger to stop Jira before doing both operations at once and release the debugger afterwards. This should make them in less then 1 second. To verify if it worked you can check times in "changegroup" table in Jira database. Look for same times in last rows of "created" column.
6. Complete the sprint

Expected result

Burndown charts for both boards show the same results as the single issue started in "To do" status and finished in "Released" which for both boards was assigned to "Done" column.

Actual result

Burndown chart for 1st board is correct (as expected).
Burndown chart for 2nd board shows no issues resolved, because it merged both transitions into one that leads from "Done" to "Released" status.

Workaround

There is no workaround