Why was my DTV visa application refused after returning to Thailand while pending?

I applied for a DTV visa in Ho Chi Minh City, Vietnam, on September 18th. On September 19th, I received a request for additional documents. I had only submitted three pay slips. They asked for pay slips for the last six months and to highlight the corresponding payments on the bank statement for the last few months. I prepared everything and submitted it on September 19th.

On September 25th, the status changed from "Pending document analysis" to "Pending approval."

But due to a problem and confusion over the dates, I applied for a Vietnam visa until September 25th instead of October 15th. So, I had to urgently return to Thailand on September 25th.

I returned to Thailand with a 60-day tourist visa exemption. And on September 29th, I received a refusal, without giving any reason.

I submitted all the necessary documents: six months' salary, a bank statement for the last six months with a balance over 500,000 baht, and certified by the bank. A letter from my employer explaining and mentioning my agreement to work remotely, also stating that we do not work for Thai clients, as well as a sample of the last job I did. The insurance certificate valid for Thailand, and the form. TM30.

I don't see what happened. Could it be because I returned to Thailand before the process was complete?