Hi Eric, changing the Locale did not work as well.
I created a ticket for this issue.
Just for sharing, the workaround for this is to use the [Created] date as today's date.
Today() function is still returning the wrong date, timezone wise.
Example, if my validation formula is = [myDateColumn] <= Today()
The workaround is to have = [myDateColumn] <= [Created]
However this workaround works if you want your validation to work only during creation of a new list item. Might not work for all scenarios.