So basically, I won Edge of Ruin (https://wowwiki.fandom.com/wiki/Edge_of_Ruin) from Trial of the Champions Heroic and of course was super happy to get such an upgrade. After about 10 minutes, the server went down for like 10-15 minutes. When I logged back on, the item disappeared from me, which I sadly noticed after entering a battleground and noticed that I was slamming people barehanded.
Equipping an item doesn't trigger a save, it's something that happens on a timer. Just a few things force an early save, like trading something with another player. Either way, you will have to get the item again in the usual way.