Workflow Email not sent occasionally

[Junsien]

Hi,
I have a problem with sending of emails where occasionally, no emails were being sent out.
The “Send Email” workflow is triggered during ALL_CHANGES event with condition ISNOTBLANK([Email Subject]).
[Email Subject] is a hidden field where it gets updated only during certain Actions for e.g. Approve/Reject.
And in these actions, I defined the [Email Subject] based on the action made by the users.
The “Send Email” workflow also does two reaction in the sequence of Email and TakeAction, where the Data Change Action updates the [Email Subject] to “”.
Below is screenshot of the workflow

An Action where [Email Subject] is being updated

Problem, there were times where no emails were being received by the intended recipients, we’ve also checked in Google Workspace Admin that no emails with the subject were received by the recipients.
The Action “Approve Country Head” has also proven to be working as expected in other times.
And in the Google Sheet source, the Email Subject column was indeed updated with the intended subject and then deleted from the cell right after.

Is this not a reliable way of managing emails, I understand that this might seem like a workaround to simplify the condition for sending emails and email subjects.
Are the actions in the workflow triggered in order? I can only imagine the data was not updated in time for the workflow to be triggered or the Reset Email Subject action was triggered before Send Emails.
Will the Offline/Sync settings affect the workflow as described above?

Any help/advice will be appreciated.
Thanks in advance.
JS