Hey there, so with the leaves being on the bottom im going against a calcium deficiency because although it has similar coloring it usually attack the upper part of the plant. With you using the sensi bloom their main pitch is not needing to ph, that its already balanced and that it contains everything a plant needs...however they do show using 4ml at this stage, so id say bump them up slightly again, maybe to 2.5 or 3ml first and watch for no more leaves being affected. If you're not already using a and b together i would suggest starting that as the auto clock is ticking away.
Good luck with the problem solving, i hope we've all been able to help some. ✌️