Volta on bar ending in start repeat displayed with no line after adding break
As reported in https://musescore.org/en/node/287768; I have seen this too but wasn't able to reproduce it once it fixed itself.
1) load attached score
2) add line break to measure 42 (the bar with the 1st volta)
Result: 2nd volta displays with no line. It fixes itself on reload, possibly other actions.
Somehow the start repeat seems to be the key - it displays properly if I delete it. But I can't reproduce for scratch using just that, and the fix-on-reload aspect also suggests there is more to it than that.