Serverless lambda logs with epoch timestamp

I’m currently getting an error when trying to fetch logs since a given epoch timestamp, as detailed here.

I am running:
sls logs -f myFunction --startTime 1590022859

And getting:
1 validation error detected: Value '-11986405200000' at 'startTime' failed to satisfy constraint: Member must have value greater than or equal to 0

Am I doing something wrong, or is this a bug? It happens on both framework versions I tried, 1.69.0 and 1.71.3.