https://www.metv.com/stories/heres-why-archie-was-actually-missing-from-two-episodes-in-season-five-of-all-in-the-family

Archie was getting lost on his way to Buffalo, but Carroll O'Connor knew exactly where he stood.

I think I remember reading the episode was filmed early in the season when he was missing and put on the back burner until he came back where they were able to finish the episode and then stuck it in mid season.
It actually works really well "Archie is missing"