Cushing Candidate?
As my followers (and detractors) will undoubtedly confirm, I am often dismissive of traces of blood in the white line. Such traces are often the result of a trauma at some indeterminate time in the past and now, often between three and eight months later, neither owner, nor horse, nor hoof have any recollection of anything untoward and at the next trim, the traces will probably have disappeared all by themselves.