Melisma line not showing on lyric extended only once

Regression from 3.0.5 to master.

Four quarter notes, click first, Ctrl+L, then type "A _ B Esc" (without the spaces - we are entering Ab on the first note with a melisma line, but then B on the very next note). We are supposed to show a short melisma line after the A and there is whole chunk of code about using TEMP_MELISMA_TICKS to make this happen, but it stopped working, probably in the fraction changeover. Not a huge deal in itself but it is getting in my way a little working on #282099: melisma underscore going backwards in multi-voice context, so I'll probably look at this too.