Stonerdanswered grow question 4 years ago Totally normal! nothing to worry about its just residue from the stem's development.
Plant looks great!! I'd suggest just increasing the amount of water you're giving her to reduce the salt buildup you have in the medium (make sure there's at least 20-30% runoff)
Besides a little Phosphorous and Potassium buildups, which are probably due to the banana tea, your plant looks very healthy!! try not to defoliate any more at this stage of flowering since you need those leaves to produce energy which produces buds!!
Hope this helps! Good luck and happy growing :)