I had a different type of multi entry non-O that I didn't want to lose in case my DTV was rejected and for irredeemable reasons (ie no point reapplying). So I left the country to apply and returned on my non-O once the DTV was approved. The immigration officer noted I had a DTV upon return and asked me to explain, I said I was going to cancel the non-O and then travel to activate the DTV. She stamped me through. I did refer to my non-O status and reasons for switching in my DTV application cover letter, as I felt it was important not to be seen to hide what I was doing. That's my experience.

I nearly did the same, it's very easy to input the country of your passport as Vietnam when actually that's the place you're applying in. Very first box on the first page of the form, is quite woolly but should read your country of passport issue, not where you're applying from as the answer. I only spotted it at the summary before submit, had to cancel the application and do a whole new one to fix it. I reckon given your reason provided in the email that's what's happened to you.

@Tod ********

thank you 👌🏼

@Lloyd *******

he's getting sorted through work, I may have got some details wrong on his but they know what they're doing. Whatever he gets I know I'll have dependent status and not right to work, so the question is for me, not him, on getting thoughts on a tenancy agreement