"If a given character is a Private-Use Area Unicode codepoint, user agents must only match font families named in the font-family list that are not generic families. If none of the families named in the font-family list contain a glyph for that codepoint, user agents must display some form of missing glyph symbol for that character rather than attempting installed font fallback for that codepoint." - css-fonts-4
The first line should render as the second. This means that no generic font was used during fallback and the first non generic font was used.