I have made short trips to Myanmar but haven't stayed there for any length of time. The Karon name I use is because I had the Bonsai beer bar followed by Our House a bar, restaurant & guest house in Karon beach Phuket.
As far as I know I am not on a watch list but who knows. I do not have a criminal record and have only ever been stopped by Customs twice in my many years of travel.
At the time I did wonder why the IO was a little abrupt this trip so there may well be something in what has been said. I will ask next time.