Like Brown Bear, I've never seen brass streaks caused by LMF browning solution.
I have seen areas where it deposited a layer of copper on the steel though.
This copper plating will happen if you apply more than one wet coat over the top of another coat before it dries.
An example of this is when one is applying the solution, if they overlap the area they just did in an attempt to make sure they have covered everything, sometimes you can get away with it and other times the dreaded copper will appear.
If it does happen, the copper will protect the steel under it so there is no way of browning that spot without sanding all of the copper off first.
The moral of the story is, if you miss a place, don't worry about it. You will cover it during the next application.