I was searching for an answer for this problem and I couldn't find one anywhere. Luckily I stumbled across the answer in game. I was having a problem defeating Leo's ghost in chapter one. No matter what sword style I used I couldn't seem to hit him.
All I had to do was to switch weapons to a torch. After a few hits he went down.
I ended up necroing a thread on here where someone had the same problem and it was marked as solved. The solution they gave was to quit using FCR. I hope this solution helps others without having to uninstall the mods you are using.

Cheers!
Ron Guiness

Either:
1) use the torch. It will always hit, but you cannot use witcher styles, so weapon skills are basic.

2) get the spectre oil recipe from Abigail ~ you will need it later anyway. It adds +20 damage (compared to +10 for the other 'creature specific' oils. This only permits hits with Strong/Fast and not Group at this stage but I preferred it anyway.

The torch is fantastically useful against Archespores though, as it damages them, and can cause incineration... allowing you to retreat to cover while the full effects of a single hit take effect, where you can recharge Igni, recover health, and then rinse and repeat.