Octave signs interacting with ties, slurs, and system breaks are a known hazard

Three specific hazards recur with octave signs: (1) a tie or slur that begins inside an octave-sign span and ends outside it (or vice versa) requires the reader to track a pitch relationship across a register-shift boundary, which is legitimate but must be engraved so the arc's shape does not visually suggest the two notes are the interval they would be WITHOUT the octave transposition; (2) an octave-sign span that crosses a system break needs either a full bracket restatement at the top of the new system or an unambiguous 'loco'/continuation cue — a bare assumption that the reader remembers the previous system's still-active bracket is unsafe; (3) a tie that crosses the octave sign's own START or END boundary (the note right before the bracket begins, tied to the first note inside it) is especially error-prone because the tie's two endpoints are notated at genuinely different absolute pitches once the sounding transposition is applied, which is correct notation but must not be mistaken by the audit engine for a 'tie between mismatched pitches' violation.

An 8va bracket ending mid-system with the very next note tied across the boundary, where the tie/slur checker (see the Ties and Slurs chapter) flags it as a 'tie between non-matching pitches' because it compares SOUNDING pitch across the octave-sign boundary instead of WRITTEN pitch.

Gould, Behind Bars discusses the system-break restatement requirement explicitly. Ross, The Art of Music Engraving, discusses the tie-across-octave-sign case as one of the more error-prone spots in engraving by hand, recommending the arc be drawn to visually favor the WRITTEN (not sounding) pitches, since the reader is reading written notation throughout. Read, Music Notation, does not treat this case in special depth; this chapter follows Gould/Ross as the more specific authorities.

This rule needs the notated content and the rendered result together — the score says what should happen, the page says whether it did.