Note: in order to be "in transit" the arriving flight to Bangkok and the departing flight to Cambodia must be part of the same reservation, must have the same PNR. Not knowing that, I had to do immigration in and out of DMK a few months ago.
well, it may happen without being posted anywhere. I'd say, Immigration has the tools to check situations like that, its up to them if they enforce it or not.
I wonder if Immigration, after your return to Thailand, will figure out that you have been in Thailand while the visa was being processed. Let us know. I will put my money on Immigration.
If I was in your situation, I will take opt 2. However, be prepared to demonstrate you extended your stay in Viet by having another hotel booking, just in case.
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