it doesn't affect buds in any normal context, so do it as much as you want :P
no nutes means deficiencies will start and that will only have a negative impact on yield... over a short period of time probably no big deal either way, but the longer it goes the bigger the negative impact on potential yield.
if you don't feed like a madman, you can fertilize up until the last irrigation if yo want to... especially in soilles grows... you aren't heavily feeding while fertilizing "on demand" with chelated nutes.
think about plants outside in great, fertile soil... how would we flush those plants? also, studies show that most of the old reasons used for flushing were completely made up bullshit by people that wouldn't know how to use an erlenmeyer flask let alone determine if mineral content is higher or lower in their buds in their garage at home. LOL. Blind taste tests also show it's complete figment that was perpetuated by people that lacked the education and equipment to draw such conclusions with confidence.
it's like people in america that don't like "obamacare" but do like the ACA... despite it being the same exact fucking thing. Bwahaha. careful of commonly accepted myhths.. they are rampant in the marijuana industry... rampant in holistic health and other snake oil salesman too. make claims based on incomplete info and jump to conclusions that make them feel good about themselves.. or worse some sort of profit-motivation.
flushing is a tool for extreme contexts... when there is some sort of imbalance or toxicity in your substrate, you flush it. otherwise, it's only a net-negative impact... even if so small you can't tell (e.g. like flushing last week or so won't make too much of a difference... sometimes i'm lazy to mix my ferts taht last week, but i don't lie to myself that it is some sort of good thing to do.. i do it when i am a lazy pud.)