HTML formatting for a column affects other columns with same name

[Jolanrensen]

Given the following example

val df = dataFrameOf("firstName", "lastName", "age", "city", "weight", "isHappy")(
    "Alice", "Cooper", 15, "London", 54, true,
    "Bob", "Dylan", 45, "Dubai", 87, true,
    "Charlie", "Daniels", 20, "Moscow", null, false,
    "Charlie", "Chaplin", 40, "Milan", null, true,
    "Bob", "Marley", 30, "Tokyo", 68, true,
    "Alice", "Wolf", 20, null, 55, false,
    "Charlie", "Byrd", 30, "Moscow", 90, true,
).group("firstName", "lastName").into("name")
    .groupBy("city").toDataFrame()
    .add("cityCopy") { "city"<String>() }
    .group("city").into("cityGroup")
    .rename("cityCopy").into("city")

// affects city, cityGroup.city, and group[*].city
df.format("city").with {
    bold and italic and textColor(green)
}.toStandaloneHTML().openInBrowser()

We'd expect only city to be affected by the format operation, but cityGroup.city and all city columns inside group are also affected.

[Jolanrensen]

It also seems that frame columns and column groups are excluded? I'd expect the group column to get black backgrounds as well in this example.