If you lock a trait, AMR will consider all options with ONLY that trait.
An item might be good for a specific trait, but if you force it to use a shitty trait, than AMR will realize an entire different item, even though weaker in total, is better then the one you have but demand to have a trait that just seems to be rather bad.
There is three ways, I would say, you can go about this.
Realize that no matter what AMR says, this trait is better for your play style and lock both the trait and item, AMR will adjust to your play style that way, but your will be less optimized.
Realize that for a proper optimization, you need to use better traits, and that might mean changing your play style a little, you will have to adjust to a more optimized play style, but AMR will tell you what to take for it.
Truthfully, if you are not a hardcore raider competing for server first; The first is probably your best option.