This was the situation with the primary
The day after the June 2 primary, only three Pennsylvania counties had finished counting mail-in and absentee ballots, according to a report on the primary produced by the Pennsylvania Department of State. Three days later, 26 of the state's 61 counties were finished. By June 17, Bucks, Montgomery and Philadelphia counties reported completion. It took almost three weeks - until June 22 - for all of Pennsylvania’s counties to report that they had finished counting.
https://www.nbcphiladelphia.com/news/politics/decision-2020/pa-election-officials-want-mail-in-ballots-counted-sooner/2512676/