Because of how Apple's webkit renders fonts, sometimes when a font has text that wraps onto another line, the text appears slightly differently than the same style on text that does not wrap onto another line. Because this is related to Apple's implementation, there is not much we can do to fix it. That said, some ways to get around this would be to use a non-transparent different color, as this mostly seems to happen with greenish hues. Additionally, you could make sure the text does not wrap across lines, or use a different font and see if that allows for consistency.