Does "queda" = "fall" as in fall over? I'm sure Duolingo was previously using "a cair" as a valid translation for "the fall".
Yes, Autumn is probably called "fall" because of the famous "falling" leaves. (Leaves leave the trees)
To fall = cair. To make a noun from this verb results in The fall = a queda.
But you can't say "a queda" for the season. The only accepted word for season in portuguese is Outono.