If you set FRotator in C++ like FRotator rotation = {0,0,0} the options are pitch, yaw, roll. However in blueprints the order is roll, pitch, yaw.
It is just a minor annoyance but it would be nice to have the BP UI updated to match the order for C++ for consistency.
so much. it have caused me to lose around 5 hours of my life in suicidal pain
why the heck…
I’d be happy if they even updated the docs (where they claim — incorrectly — that the parameter order is pitch, roll, yaw). Even though experimentally it is clearly pitch, yaw, roll as you said.
My guess is that the parameters are meant to be pitch, roll, yaw, and this is just a bug. That hasn’t been fixed since at least 2015. 
I thought I was becoming insane for a few minutes when I forgot how this worked today. Are all rotators like this or just SceneComponents’ ? I ask because mine is actuall Roll, Yaw, Pitch like WTF, so I think it has something to do with component hierarchy.
I was also going crazy with this until I figured out. Good god what the hell is wrong with this ■■■■? Why is the order different??? I want my 4h lost back!! 