Agree, but the problem would appear to be that those 138,339 ballots are now mixed in with the big pile of millions of other votes, and you’ll never find them to see if the down-ballot votes ALSO went 100% Dem - which of course, they didn’t.
That can be solved IF there is a unique timestamp for every vote run through the counter.
You can therefore track the count for each question on each machine over time.
Segregate the *results* from after (say) 1 AM or 4 AM.
Compare them to the results from known same-day votes.
Unless they zeroed out the machines to feed the new ballots through.