Why isn't the time of my Google Task automation syncing correctly?

This is currently a technical limitation of the Google Tasks API. It does not allow the time of a due date to be recorded:

https://developers.google.com/tasks/reference/rest/v1/tasks#:~:text=The%20due%20date%20only%20records,is%20due%20via%20the%20API.

We'll keep an eye if Google changes its API to allow us to add the time to due date.