Spot the bug in the value-class map key

from Inline value classes
Kotlin 2.4.10 intermediate 4 min 1 issue to find

This value-class key must remain retrievable after insertion. Find the bug.

kotlin
@JvmInline
value class Labels(val values: MutableList<String>)

fun main() {
    val labels = Labels(mutableListOf("paid"))
    val counts = mutableMapOf(labels to 1)

    labels.values += "priority"
    println(counts[labels])
}
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