> Before a hyphen at the end of the line a long ſ must always be used, for example Shaftſ-bury.

That's when hyphenating a word, not between different words linked by hyphens.

That's exactly what a hyphenated word is.

No. "Hyphenating a word" here means when a whole word is split by a hyphen to continue on the next line of a justified column of text. In that case only, a long s is used before the hyphen.

The hyphen is not at the end of the line. Shaftſ-

bury is just Shaftſbury with a hyphenated line break.