Weird (bug?) behaviour in Black Cat game

[YooperJake]

Game#: 130541634

Somewhere around turn 12 (?) I played an Artificer and discarded to gain an Estate.  My opponent reacted with Black Cat x3.  Somehow, those Curses ended up in my next hand, even though I hadn't shuffled.  Wondering if it's some weird unintended side affect of a React to an Artificer gain (which top-decks).

Thanks for any insight - Jake

[Ingix]

According to the log, the Sentry you played after the Artificer caused the shuffle: