I wasn't able to reproduce this exactly but it very much points to issues with either the server time, the time on your computer or some sort of timezone issue.
If you could let us know if this is happening on other time stamps, that'd be useful to know (most relative times, such as the ones on posts, can be hovered over to see the absolute time).
Also could you clarify exactly which timestamp was correct? Was the poll ending "Today at 7:45 PM" (Nov 5, 2020) or was it ending on "Dec 1, 2020 at 7:45 PM"?