In a standard ranked game, my opponent played The Primus and used its unholy ability. I played reverberations and used the blood ability, then returned the copy of The Primus to my hand using Saloon Brewmaster.
Later in the game, when I replayed the bounced The Primus, each of its abilities happened twice when used. I gained health twice from the blood ability, summoned 4 tokens with the unholy ability, and got 6 spell damage from the frost ability. I still discovered one card each time.
When recreating this bug with my friend we realized that it also locks out the opponent from playing the game. They always see it as enemy turn while I am waiting for them to rope.