Kalista's W is bugged
It used to be that Kalista's bound ally could last hit creeps using the passive damage on W, and it doesn't work that way anymore. There are no changes that I can find that explain this.
Old: Kalista gets a creep low, support auto attacks and executes the creep granting Kalista the gold. Live: Kalista gets a creep low, support auto attacks and executes the creep granting the support the gold.
TLDR:
broken pls fix