I was using once BioBizz nutri's.
And I didnt flushed, just harvested.
Smell and taste of that weed wasnt good, it was like smell of that fertilizers.
That was my first grow ever. I dont make that mistake anymore.
Maybe its a myth, I dont know.
Im sure it depends which nutri's u uses.
Once girls feels lack of nutri's, they uses all available, not only in the soil, but in leaves too, dries them and pumps nutri's in flowers.
Maybe that stimulates to final ripen.
In my opinion, theres no reason to not flush.
But u will do whatever u want.
Bless