Duels Turalyon Hero Power summoning silenced minions

I was playing Warlock Drek’thar in duels against a Turalyon with the resurrect hero power. At one point, I silenced and destroyed a Leviathan. Strangely, when my opponent used his hero power and resurrected the Leviathan, it came back silenced, though it still had divine shield, and it did not come with the appendage though it normally should.