DateTime in repeat not showing correct data

I think this is a bug but wanted to make sure I was doing it correctly. I have a list of objects coming from a datasource, one of the attributes is a Unix date value (eg. 1620954000, called dt, it comes as an INT not a string too). There are 7 items in the list, each with their own, unique datetime value. I have a Row that is set to repeat on each object in the list.
Doing some testing I’ve found the below.
Column 1 is the raw current.dt value from the datasource and displays correctly. 1620867600 (this is GMT Friday, May 14, 2021 1:00:00 AM)
Column 2 = DATETIME(current.dt) - Displays 1970-01-19T18:14:27.600Z
Column 3 = FORMAT_DATETIME_LOCAL(DATETIME(current.dt), “DD/MM”) - Displays 20/01 (my local timezone +10GMT (this is the way I want the data to display)

Can someone please explain why the DATETIME function is not performing correctly? Do I need to do something different?

I fixed this. I used to help me understand times etc and it turns out DATETIME needs the EPOCH in milliseconds (as the documentation does say). So I just multiplied the value from the API by 1000 and its good to go.