If I recall, a couple of quarters ago Tesla already made an adjustment to their warranty reserves so they could recognize a larger portion of warranty reserves as income. For years Montana Skeptic has been harping on Tesla's "unrealistic" warranty reserves and how this was going to come back to bite them. He said it was fraudulent and Tesla knew there wasn't enough in the reserves for all the issues they were going to have to deal with.
But Tesla looked at the data which showed they had been overly conservative and had been reserving
too much in warranty reserves and adjusted it, dropping more earnings to the bottom line. Pretty sure Montana Skeptic just doubled down and claimed Tesla was increasing the level of fraud!
In any case, the recent wiring harness business doesn't amount to a hill of beans - most of the warranty reserves are to address the possibility of large scale battery recalls like the Bolt is experiencing.