Multiple lyric verses maintain consistent line-to-line spacing without a melisma extension colliding with the next verse line

When a piece carries multiple lyric verses stacked below one staff, each verse line sits at a consistent vertical increment from the one above; a melisma line/extension must not visually collide with the next verse's text.

Verse 2's text renders at an inconsistent y from row to row, or a melisma dash-line from verse 1 overlaps verse 2's syllable text directly below it.

Gould, Behind Bars, ch. 'Vocal music', multi-verse lyric layout; Ross, The Art of Music Engraving on stacked lyric lines.

This rule is about where marks land on the page, so it can only be judged after engraving. Collision and spacing faults live here.