acts_as_versioned small question

I have this in the RSL model:

acts_as_versioned
self.non_versioned_columns << 'rsl_verified'

When I perform this ajax action it still updates the version table
when I toggle this value in the RSL table.

@rsl = Rsl.find(params[:id])
@rsl.update_attributes(params[:rsl])

The column that gets sent is the rsl_verified.

The version table does not have that in the version table but still
updates the version table. Not sure why.