Game ID 16009. I won with [Mixed Greater Terminals, All Triplets, 2 Kong, West] but was not credited with Small Three Similar Triplets as well. I had a (large exposed) kong of 1萬, which is what I believe might have caused the pattern not to be recognized for whatever reason. Please look into it!

Yes, it is a bug and it is because I did not consider kongs when counting triplets in this case. It is fixed! thank you, dax00!