while it could be possible that somehow the NaCl in sweat could cause this i would find it more likely that it is something with your washing machine because if it was a salt thing i would think that the spots would be mainly where you sweat the most, around the neck line, arm pits etc. instead of just randomly on the clothes and i wouldn't think they would be spot and instead just be a really faded place looking like bleached jeans like is popular currently.
If it were me i would just be sure to wait for the washer to finish filling and put soap in the washer before i put clothes in it, thats what mom said(idk how to laundry really, i just turn it on put soap in it and whatever clothes are dirty at the time) but even with cf and a bunch of salt when i sweat which is like all the time i don't get bleached spots. i'd check on my washing machine
If it were me i would just be sure to wait for the washer to finish filling and put soap in the washer before i put clothes in it, thats what mom said(idk how to laundry really, i just turn it on put soap in it and whatever clothes are dirty at the time) but even with cf and a bunch of salt when i sweat which is like all the time i don't get bleached spots. i'd check on my washing machine