I just noticed this, as my default timezone is -5, I changed it and noticed that the -4:30 is missing in the Board Settings > Date and Time Formats in the admin CP, it appears in the user CP normally.
I'm Using Beta 2.
Hi,
Thank you for your report. We have pushed this issue to our Github repository for further analysis where you can track our commits and progress with fixing this bug. Discussions regarding this bug may also take place there too.
Follow this link to visit the issue on Github:
https://github.com/mybb/mybb/issues/904
Thanks for contributing to MyBB!
Regards,
The MyBB Group