That's classic N deficiency. Super common to see a couple weeks after folks switch to bloom nutrients with insufficient N.
I like to use veg ratio all the way through the cycle including flower, the only time I use bloom ratio ferts is as a small dose added on top of the veg nutes, say 70/30 - veg/bloom, and I only do that for the first half of flower or so then taper back to low dose veg nutes to finish.
Alternately some people like to use veg nutes for the first 2-3 weeks of flower and transition to bloom nutes after the stretch. You just need to be careful not to stunt the bud growth with too much P doing it that way.
I've never really had great results using bloom nutes from the start of the flower cycle. It just has too much P and too little N.