Fillep Waltz; Human Sorcerer Contriver perk
GSID: PupEfUR
I asked on IRC and did a search but I can't find any documentation on a duration change other than Shelgarn's Persistent Blade should be turn/lvl. When cast it lasts only 1 rd/lvl, or something very close to that.
This is cast, not from an item or ability.
We were aware of this and it is not intended. It may be addressed at some point. Thank you for the report nonetheless.