At present the strike-out line is positioned in the center of the glyph frame:
y = roundf(runStrokeBounds.origin.y + oneRun.frame.size.height/2.0f + 1)+0.5f;
It would be more correct to position it at half the X-Height.
Since glyph runs have the same font, it should be possible to get the actually used font, get the x-height from that and use this for correct positioning.
fixed in 1afd065