Hello,
some weeks ago, i played Kullervo and noticed my Komorex second zoom fire was extremely slow. I went after the mission to see the build : it had mods to increase fire rate. I used another warframe : the second zoom fire (explosion mode) was firing way faster.
Today, i played another Kullervo build, and the Lex Prime with incarnon. I noticed my incarnon mode was firing super slowly. ...and it isn't that slow at all with another warframe.
I think something's causing Kullervo to lose fire rate / not take mods in count to properly calculate weapons fire rate.
I can do more precise tests if needed.
I didn't find any post reporting this when searching for "Kullervo fire rate".