Treasure Hunter not gaining Silver after Delve

[ffejselur]

R gained a silver via Delve. The next turn I played a Treasure Hunter and some treasure and bought a Sir Bailey. I should have also gained a Silver "per card the player to your right gained on their last turn". (I looked at w.ds to verify this) Log excerpt below: (note: the player to my left gained nothing his previous turn, but that shouldn't matter)

Turn 4 - Revenge Witch
R plays a Potion
and 3 Coppers.
R buys a Delve.
R gains a Silver.
R shuffles their deck.
R draws 5 cards.

Turn 5 - ffejselur
f plays a Treasure Hunter.
f plays a Silver and 3 Coppers.
f buys and gains a Sir Bailey.
f returns a Treasure Hunter.
f receives a Warrior.
f draws 2 Coppers, a Silver and 2 Estates.

Joining game #494686 on frankfurt.

[Watno]

I investigated this and the issue seems to be a confusion of left and right (on our side).