I have my board time zone set to EST (UTC-5) and when I define the sprint dates I assume it will be in the same time zone, but it is not. For example if I set the sprint end date to 12:59 PM, then in Jira Advanced Roadmap (in my configuration I use target dates), then when that information is missing, it takes the dates from the sprint, and it is shifted by one day. I did several test and I realized that for 6:59 PM it doesn't change. So internally the date is stored in UTC-0 (Greenwich Mean Time (GMT)). I talked to my Jira Admin and our Jira instance is configured to CST (UTC-6) via the field: Default user time zone, so it is not taking that time zone neither. When you setup sprint start and end dates you don't have the option to specify time zone, I assumed my board or personal setting, but it is not working like that.
- Is there any Jira Instance or Project settings specific configuration to control this?
- Is it correct my assumption that the time zone for sprint is always UTC-0 regardless of the Jira instance time zone settings or board settings? Do I need to put the dates and time always assuming UTC-0?, but then it will show the wrong information in the backlog view in case there is date shift between my time zone and UTC-0.
- Is it a bug?, because at the end it is confusing, because it shows one day in the sprint information view, but at the end is a different day. Was it reported?
Here the screenshot of my sprint dates:

Here Jira Advanced Roadmaps showing the dates shifted

I also tested using Automation that when I try to assign the sprint date to another date field, it is also showing the next day.
I searched for a similar posts, like this one: Issues with a Sprint START and END date that provide some explanation, but it doesn't really solves it. Similarly with Jira time zone post.
Thanks for any help,
David