Jira Web UI and API yield different query results

[S Isaac]

I'm running this JQL in both the web UI and API and getting different results:

project = {key} AND created >= 2021-06-25 AND created <= 2021-07-02 ORDER BY created'

The web UI returns 8 issues while the API returns only 7. I have checked the issue creation dates thoroughly and they are all created between the time frame above. The issue that is missing from the API search results has a createdDate of 2021-07-01.
The user I'm authenticated within the web UI has timezone of CST. The user I'm authenticated with via the API also has timezone of CST.
It's not a user permission issue either because if I change the end createdDate from 2021-07-02 to 2021-07-03 for the API, it does return all 8 issues.

I think this is a bug. Please help. Thank you. 

[Brant Schroeder]

@S Isaac Welcome to the Atlassian Community

In Jira you can choose the timezone of the server.  You can set it by following these steps https://confluence.atlassian.com/jira063/choosing-a-time-zone-683542442.html

Default time zone : This is the time zone used throughout the JIRA interface. Users can  override the default time zone by using the Time Zone setting in their user profile.

Are both user accounts on the same time zone?  What happens if you use the same account on the API and the user interface do you get the same results?