New set card disappeared after opening a golden version

I just got a golden legendary in Hearthstone (Talgath) on the Europe server, but I already had the normal version of Talgath. When I went into my collection to check, the normal version was gone!
I wasn’t offered to reroll. The normal Talgath is just gone.
Blizz support told me to submit a bug report, so here I am
Any way to get me my legendary back? I feel scammed and it’s horrible