Issue Summary

Inconsistent SLA Calculation for Tickets Spanning Multiple SLA Calendars (Regular and Unique Calendar Month)

Description:

JIRA currently calculates SLA based on the active SLA calendar at the time the ticket is active or closed. This results in incorrect SLA totals when tickets remain open across a transition between different SLA calendars.

For example, if a ticket is logged before a unique calendar month (e.g., with regular SLA timings of 9 AM–6 PM) and continues to be processed during the unique calendar month (e.g., with adjusted SLA timings of 10 AM–5 PM), the time already consumed under the regular SLA calendar is not accurately combined with the time consumed under the unique SLA calendar. This causes discrepancies in the final SLA calculation.

Steps to Reproduce

Step 1:

• Open a ticket before the unique calendar month, when the SLA is governed by the regular working hours (e.g., 9 AM to 6 PM).

• Allow the ticket to consume some SLA time under the regular calendar.

Step 2:

• Switch to the unique calendar month SLA (e.g., 10 AM to 5 PM).
• Continue working on the same ticket during this unique calendar month.
• Close the ticket either after the unique calendar month ends or while the calendar is still active.

Expected Results

• SLA calculation should combine the time accumulated under both the regular and unique SLA calendars.
• The system should preserve the historical context of each SLA calendar applied during the ticket's lifecycle, instead of recalculating everything based solely on the current active SLA calendar at the time of closure.

Actual Results

JIRA calculates the entire SLA using only the current active calendar (e.g., reverting to the regular SLA after the unique period ends), leading to incorrect SLA totals for tickets that span across multiple calendars.

Workaround

No workaround is currently available.
The issue stems from JIRA's behavior of always using the currently active SLA calendar, rather than tracking and combining SLA time under the respective calendars in effect during the ticket’s lifecycle.