I posted about my two recent experiences going through the Thai border in a TDAC related thread over in the Qatar forum, including one where I managed to submit an incorrect arrival date on one entry.

As we're not supposed to double post,

I'll link to that posting here
https://www.flyertalk.com/forum/37130168-post20.html

And a link to the thread (post posting was #20 in that thread)
Thailand Digital Arrival Card - BKK and more