Even on NASA.gov they state:

Wait, which part is wrong then?

You calculated a distance of 120M miles given their report of a speed at some point in time. Yes, that doesn't exactly match the 146M miles that the reporter is stating the spacecraft travelled so there is obviously a discrepancy there, but first, that's not that big of a discrepancy and second, that's an error of someone getting the numbers not quite right. What it isn't is in any way a problem with the physics as I have explained it.

You will note that the TITLE says 300M miles and the ARTICLE says 146M miles. The title and article were not written by the same person. Maybe the person who wrote the title read the article and figured it was a round trip, so the probe would have to travel 146M x 2 ~ 300M. Who the fuck knows. Who the fuck cares? These evidences of bad reporting in no way signify a problem with the physics, just with the reporting.