Either Rotten Tomaotes do not have good forecasters, or WB (which has a part ownership stake with RT) has really questionable marketing.
WW84 is the 2nd time WB/RT have pulled a “Certified Fresh” but, it’s really not, like it did with JOKER last year.
They basically put most of the positive reviews in early first, enough to “certify it fresh” to hype its release and put it in their marketing, before slowly adding the negatives. By then no one cares, since the premature certification did it’s job for the marketing.