I've heard of a preflower flush when you switch to 12/12 but otherwise if your numbers are stable, PH EC going in and coming out, then I would not worry about it.
Good Luck!
You should definitely doing a flush watering everything 3rd feeding. I personally do 2 feedings one watering, I water 2L/ .5 gallon every 2nd day in 5 gallon pots in flower and it works well for me.
With your medium, if your nutrients are not organic, it is recommended to have plain waterings every other/every third feeding to reduce salt buildup from synthetic nutrients. Plants are looking gorgeous!