Possible bug with end of season rewards? Help pls.

So I've got to 12 ranked (no, not 12 overall legend, lol, I'm a casual) and I opened my rewards. It showed me I've got some gold cards (I'm sure about fist of jaraxxus and that 3/5 priest card that att gets buffed by 2 when someone is healed, not sure about 3rd) and some dust.

So i opened my card library to dust the golden cards I've got but they weren't there. Insted the game somehow showed me that i have 5 new cards, like i opened packet or something. I won't bitch about it because it turned out that i got 3 epic weapons (1 paladin and 2 for shaman) and 2 other cards i dont even remeber them. When i restarted the gold cards were there again, but the epic weapons haven't disappeared! And no, i didn't open any packs during this time. I'm just courious is it normal? What happened?

EU, my IGN fifax if anyone is curious