When playing Berserker against raider, mid chain, both our HA attacks go through. However, Raider seems to be stopping my Berserkers chain in favor of his own.
Berserker have HA on chain attacks/feints only after 100ms and Raider (and every other hero) can hit you between attacks or feints (most likely) and in first 100ms of your attack, maybe he is just lucky, I don't think it is possible to use such knowledge consciously.