Good question — I believe they are reported in the central precinct, but at close. No early votes are “counted” before the close, but the machines obviously counted them each day. The official “counting” is when the workers read out the totals from each machine. They do NOT read the early voting machines until the close of the election.
One thing extra to remember about Fairfax County is that they screwed up very briefly on election night, at some point they accidentally added 100,000 votes to Biden’s total, because of a math error (these are remarkably common in the unofficial reports, people read a comma wrong as a 0, and “11,230” becomes 110230).
They realized the error quickly, and updated with the correct information. Some people screen-capped that huge Biden jump and never realized it went away a bit later.