Font glyph issue: vertical colon movement

[notpeter]

While coding in Rust I observed an odd behavior where the colon glyphs dance as you type them.

To reproduce type out the following:

fn family() -> String {
    String::from(std::consts::FAMILY)
}

The colon(s) move twice: First, when you type the second colon (horizontally) and then when you type a letter after (vertically). No idea why the vertical movement only happens inside parens.

[notpeter]

The Iosevka customizer doesn't currently support defining variants for the ':' character, but I opened an issue to see if they might in the future. In writing that up I also discovered the :: sometimes dances up or dances down or just stays put depending on context. Fun!