YES.
potassium or something in it that does it.
I messed around with BSM as a source of minerals and potassium for a couple runs and ran into toxicity issue with about two weeks left (on a long sativa).
Being a diagnostician, I systematically eliminated each (new) thing until the problem went away, the issue was too much BSM, as to what exactly in it, I can't say, but an educated guess would be too much potassium.
I used on tablespoon per gallon of water, once a week. and that proved to be too much.
BUT I do use well water, so it's possible it was something other than the potassium.
All I know is the problem went away when I stopped using it.
in my opinion BSM should only be used as a source of food for microbial populations. Like AACT and such.
Epsom is a good thing to use, albeit sparingly, all depends on the quality and hardness of your water though, also your soil mix.