Understanding Mixpanel Timestamp Timezone Differences in Exported Data vs Dashboard

I've been having some timezone issues with timestamps from the export endpoint, where the timestamp of exported events is 5 hours off from the timestamp of the same events in the Mixpanel dashboard. I found this on the documentation, and I'm thoroughly confused... what does it even mean for a timestamp to be in a time zone? Aren't timestamps UNIX time, their whole point being they're the same everywhere?

For projects created before 1 Jan 2023, Mixpanel converts event timestamps to your project timezone before writing the event to your Mixpanel data stores, meaning that event timestamps are stored based on the project timezone setting at the time of ingestion.

Does this say what I think it says, that timestamps for older projects need to be manually shifted by the UTC offset of that project's time zone in order for them to be correct? How is this not a major bug?