Sprint date inconsistency, can I modify the start/end date of closed sprints?

[Veronika]

Just started my new sprint (sprint 80), when i realised something went wrong last sprint (sprint 79).

Today i tried to open the new sprint (sprint 80) with 19/Jun/25 9:54 AM - 19/Jul/09 9:54 AM but received the error "The start date of a sprint must be before the end date"  and somehow landed up with this:

- Active sprint 19/Jun/25 9:54 AM - 32/Jul/02 9:54 AM - sprint 80

- Closed sprint 12/Jun/12 11:37 AM - 19/Jun/25 9:49 AM - sprint 79

- Closed sprint 19/May/28 9:41 AM - 19/Jun/12 11:36 AM - sprint 78

- Closed sprint 19/May/14 12:17 PM - 19/May/28 9:40 AM - sprint 77

I am able to update the active sprint dates in backlog, and it takes effect in the active board also, but not sure if at the time of closing the sprint will be so too. 

In any instance, i have sprint 79 that started 7 years ago based on the system, not sure how to correct it. 

[Andy Heinzer]

Hi Veronika,

It looks like there is something strange in regards to the dates themselves being used here.  I would expect this formatting to be in a day/month/year format, but from looking at your values here, I'm not sure that the dates listed there are actually accurate to the sprint data.

Before we try to change the dates of the sprint, I'd like to know more about your Jira environments settings to see if perhaps this problem might be brought on by a specific setting change.   Could you let me know if this is Jira Cloud or Jira Server?   It might make a difference in the way we troubleshoot this.

But in either platform, if you can navigate to the JIRA_URL/secure/admin/AdvancedApplicationProperties.jspa  and then let me know what values you have set for

jira.date.picker.java.format
jira.date.picker.javascript.format
jira.date.time.picker.java.format
jira.date.time.picker.javascript.format

If these have been customized at all, you tend to see a 'revert' button next to the current values, but either way I'm interested to see the specific values you have here.  A screenshot could be helpful to better understand if the strange dates we see in the sprints might be a symptom of a bigger problem here or not.

Please let me know.

Andy