According to the token text of Karox Bladewing, it is supposed to deal 2 damage upon entering the field and then at the beginning of your turn if there are 8 or more red gems. The token is doing 3 damage upon entering the field and then 4 damage at the beginning of the turn. I’ve encountered this both when I’ve controlled the token and when the opponent has. I’ve checked both Verix Bladewing and the Karox Bladewing token to see if there is anything that is supposed to be adding the additional damage, but have not found anything that would impact the field in this way.
Karox support is not the only one with this problem. From what I remember, Goblin Chainwhirler, which is supposed to do 2 damage to creatures and players on EtB, also deals 4 damage instead.