Yet another weird counterattack interaction, this time with injure

I’m not too sure what jarlaxle’s injure all attack is but in a pvp match, opponent’s Jarlaxale injured my party. My tommus has a 40% chance to counterattack due to those gloves of his. He does not have taunt+counterattack.
My tommus moves up to middle row, does NOT trigger boots extra action and ends turn. Very oddly tommus takes injure damage and procs counterattack on jarlaxle.

No idea what has just happened.

Jarlaxle has an item that will makes an attack of someone come in melee range of him

@Krom is spot on with the counterattack comments. Jarlaxle’s injure all attack is a poison attack.