All waypoints treated at spline?

Arducopter 3.1.5
it seems to me like all waypoints (type 16) are treated as spline waypoints. , the flightpath is nicely curved.
Is this a known bug ?

My copter tracks waypoint to the T so hard abrupt turn for the next waypoint. Pretty excited for spline waypoint.

forgot to mention that was with 2m radius, and 0sec delay.

I had this issue too. I had a default Auto program that I ran and it made large turns in 3.1.5. I re-entered the program and left out some Condition_Yaw and the issue went away.