i checked several times and finally find the problem:
if you want to count the number of answer Y1 and answer Y2,
countif('Y1' OR 'Y2',rg1_SQ001,rg1_SQ002,rg1_SQ003,rg1_SQ004)>2 not work well.
countif('Y1',rg1_SQ001,rg1_SQ002,rg1_SQ003,rg1_SQ004)>2 work well.

countifop('=','Y1' OR 'Y2',rg1_SQ001,rg1_SQ002,rg1_SQ003,rg1_SQ004)>2?
i am not sure if that's a bug or my mistake?