A bug in Dark Souls II caused weapons to degrade at double rate when played at 60fps and "durability was decreased drastically when attacking enemy corpses, friendly characters etc." (source, I'm not sure if the latter issue is linked to the frame rate).
This issue has been fixed.
Source - dated May 2015.
To note however, that while a lot of players have had issues with the Dark Souls games (especially on PC), FromSoftware have often had a very strong "Deal with it" approach to player complaints, often stating that apparently "buggy" features are working as intended; the latest being the Dark Souls 3 "poise bug".
The reason for this approach is that firstly; the game was developed to be difficult; often phrases like "frustratingly difficult" being used to describe it. After all, the tag line for the series is "Prepare to Die". Secondly; the game was actually developed by the dev team, for the dev team*. That is, they developed a game that they wanted to play. They created the features they wanted, they created the challenges they wanted. Effectively, we're actually playing somebody else's game.