Here's the article from the Sacramento Bee that's the basis of the Fox News article:
Misconduct claim involving Kamala Harris aide came to agency months before she left office
There's nothing in there signifying that Senator Harris knew about the notice. The article states that when Harris's office received the notice on October 3,
Noting that Hartley had sought an immediate right to sue, the intake analyst wrote that “No action is required by the Department” and referred the complaint to “Intake Results.”
So it was misfiled. Somebody didn't pass it up the ladder when they should have. That being the case, there's nothing there to say that she knew about it and ignored it.
Now, if something later turns up refuting that, then she deserves to be raked over the coals. If she can't handle this two years out, she'll fold like a cheap card table if she decides to run for President.