Changing the DST setting for an invalid date-time is a bad move.
If you do not know the date-time (because it is not valid), then you
do not know whether it is the date at which the change should occur.
The date of the change is different in different timezones, and if the
date-time is incorrect,
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/10/datetime-invalid-input.html
Description:
This page
https://www.postgresql.org/docs/10/datetime-invalid-input.html
says a translation by +1 hour occurs for hours between 2 AM and 3