100 hours of gameplay and only come across one almost game-breaking bug with Ranni's quest chain. I missed a part of a quest and the certain NPC's weren't available in certain spots unless you did them in one order. Thankfully you could continue the chain by killing a certain boss.
Apart from that no major bugs or glitches encountered. I did glitch out and cheese Mohg though, with the running wall jump exploit. I cba'd that one lol.
Still an amazing game and released in relatively polished state among most big AAA RPG's releases.