Hi, @SChang
I am glad to hear your issue has been solved.
Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others.", and according to the scenario introduced here: Answering your own questions on Microsoft Q&A, I would make a brief summary of this thread:
Issue Symptom:
Office 2019 Not Updating Automatically
Current status:
Sovled by SungChang-8321
Solutions:
modify the "Office Automatic Updates 2.0" scheduled tasks with "/update user" instead of "/frequentupdate SCHEDULEDTASK" in the argument list
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