The Date/Time Formatter action does not provide an exact timestamp. The X (Unix in seconds) time formatting end up rounding to the nearest minute, making timestamps generated this way useless, as they are not unique. The result is even worse on the x (Unix in Milliseconds), where it not only does not include any millisecond data(just 3 more 0's/decimal places), it will even round to the minute.

My current workaround is to use a Custom Code action:

"const timestamp = Date.now();

output = { now: timestamp};"

This provides an accurate Unix timestamp, but we should not have to use a premium action due to a bug in a standard action. It appears as if the Date/Time Formatter action is batching or rounding it's timestamp lookups.

Here is a Loom of the situation: https://www.loom.com/share/680fc97d875842c3aa8c3382b64a0cbb