Line spacing in text too wide at first, changes after layout

Windows 7, GIT commit: c7b7d35

I don't know if this will turn out to be reproducible for everyone else, but it is for me.

1) new score for flute
2) click a measure rest
3) Ctrl+T
4) type "staff text", Enter, "line 2", Esc

Result: the second line is too far from the first. On my system, with all default style settings, the second line of text overlaps the top staff line.

5) Ctrl+A

Result: the spacing closes up; line 2 jumps up a few pixels and now sits on top of the top staff line rather than overlapping it. Hard to say, but I guess this is now the correct / expected spacing.

When I set a breakpoint on the places in Text::layout() where _lineSpacing is set, it seems it is being set to 14, 16, or 20 depending on I have no idea what. It's all the same font - the default Staff Text font - so I don't see why font metrics should ever return anything but the same value.