1. IntIdTable is just a shortcut for IdTable with int autoinc primary key. If you inherit from it and override id with foreign key it looks like something wrong. Why you want to use IdTable in this case? Maybe just

object PlayerDataTable : IdTable<Int>() {
    override val id = reference("player_id", PlayersTable)
}

2. Registering column even on overrided field looks like a Kotlin bug imho (implicit call for super.id ?). Will try to investigate what's really happen.