Issue Summary

Following a recent change to how SLA time format is determined, some customers are being switched to 24hour format with no ability to change to 12hour, regardless of their language/locale settings. The change is noted in the change log for Atlassian Cloud changes Feb 6 to Feb 13, 2023:

Made SLA time formats consistent with locality

[ROLLING OUT]

Previously, the date and time formatting for SLAs did not match the formatting of other displayed dates and times in Jira Service Management. SLA date and time formats will now display correctly based on each user's locality,

Steps to Reproduce

Some users are experiencing the issue seemingly spontaneously. However this can be reproduced like so:

1. In your atlassian account settings go to Account Preferences > Language & Region, and change your language to that of a region that typically uses 24hour time formats, such as "English (UK)" or "Português (Brasil)"
2. Wait a few moments for the change to complete, then change it back to your original language
3. Navigate to a project and view the SLAs on an issue or in a queue

Expected Results

The time format of the SLA should change based on your chosen language, and should be in 12 hour format for languages correlated to regions that use 12 hour, and should be in 24 hour format for languages correlated to regions that use 24 hour.

Actual Results

Once the SLA time format is in 24 hour format, it cannot be changed back to 12 hour format regardless of the chosen language.

Workaround

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