Update: made it through immigration. This is my fifth visa exemption this year. I extended all of them so been here quite a bit.
The officer said:why you come to Thailand. I said: travel and added that I'm meeting up with a friend then traveling to penang. My onward ticket could corroborate.
Then he said: you come Thailand many time?
I said: yes, I really like Thailand.
Then I just shut my mouth. After a while I heard the stamp.
I think the fact that it was 23:10 must have helped.
Also. Air Asia asked me for onward ticket at counter in Macau. I had a bus ticket from hat yai to penang.
I'm not eager to do this again this year. It was way to close for comfort.