Incorrectly rendered glyph (colon in Roboto)

To reproduce: Take the example examples/image.rs and change the font to Roboto-Regular and the text to anything that includes a colon, for example let text = "::::::::::";. The lower one of the two dots in the glyph is not fully rendered.

Increasing the size of the bounding box of the glyph reveals that the lower dot is shifted to the right: