This happened in CA in 2018. On election night, I was pleasantly surprised to see a lot of GOP wins and some of the propositions I voted for or against actually winning. And the next day, all of that was reported as wins.
And as the week went by, slowly all those wins were quietly erased as mail in votes were counted. I was so sad. . .
I do predict something similar this Nov. Dems have learned how to do ballot harvesting well from CA.
Not mail in votes counted, what you saw in Cali 2018 was ballot harvesting. Illegal in most states but not in Cali.
Is CA a universal mail in ballot state?