It's hard to tell without looking at your project.
If you take the example and just change the GetDate function to return Date.Get(2021, 11, 12, 19, 0, 0, 0), the count down works as expected. So I imagine that in the process of copying and pasting you maybe forgot something or there is something that needs to be changed and you missed it.
The parameters for the Date.Get expression are as follows:
year => 4 digit number
month => 0 to 11
day => 1 to 31
hour => 0 to 23
minutes => 0 to 59
seconds => 0 to 59
milliseconds => 0 to 999
So Date.Get(2021, 11, 12, 19, 0, 0, 0) should get you the date for December 12th 2021 at 7pm