Early returns often do not reflect the final vote count. Happens every election. This election was a bit unusual, usually the Dems are ahead early because the big cities are quicker to tally and report the vote, and the cities are more democratic than the rural areas. In this election the Democrats encouraged voting by mail, while the republicans discouraged it. Dems are generally afraid of covid and Reps generally are not. So of course the mail-in vote, which was counted later, was heavily democratic. The article claims statistical improbability, but lacks the mathematical rigor to prove the claim.