I have a problem with quest with berengar's blade.

After killing the monster i found bag with recipe but when i come close to this bag it disappears

any one know how to fix it ??

If you already have the diagram for Tor'haerne, which you can find in a guarded treasure in Velen, the bag will not be necessary, because that's all it contains.

yes i had this recipe but i couldnt end the quest cause of this bag but it is solved now.

i made verify/repair but it didn't work and i reset my computer

after reseting i loaded the game and everything was ok and now i have two recipes for Tor'haerne