Honestly they dont look that bad, I mean I realize they're yellow but happens alot last few weeks of flower, some sooner and more signifigant, but overall they plant looks healthy, IMO. I would just continue on with your tiger bloom before flush, Im not that good with diagnosing but Ive had perfectly good plants look similar in my grows and worked out fine. Continue checking, maybe someone else has a better explanation but I wouldnt be that worried, wish you all the best, those buds look like there comin along good...take care, peace