Hi. have a problem with this quest, in few words, this target does not fall
https://s31.postimg.org/5f4el6xvr/witcher3_2016_07_04_11_55_18_62.jpg[/img]

impossible in this condition complete the quest without a defeat. Someone know how to solve the problem?

No error message or other, just this target doen not fall. Have a Gog version of game with HoS and B&W, with this few mod list:

- Super Turbo lighting Mod 2.2
- Rune Slot
- No painting Effect
- Next Gen Candels
- Kill count 1.22
- Increased LOD 1.6b
- Immersive Cam 2.6.1
- Geralt enhanced wind effect hairworks 2.7
- Fast Travel from roach for 1.22

txn in advance.

This is a unknow bug?

nice, i'm lucky....

The proper English name of the quest is The Warble of a Smitten Knight. It had some bugs, but it was a problem with Roach stopping to respond, thus making it impossible to finish this quest. It was fixed in last few patches. I hope you will find solution to your problem. Cheers!
Edit:
https://www.reddit.com/r/witcher/comments/4lvvwr/spoilers_bnw_quest_warble_of_the_smitten_knight/
It's the immersive cam mod. Try to remove it and check if it works.

And I was supposed to do some research on laser materials...