Hi,
I've never experienced this problem before. Which version of Vizard are you running? Have you tried just retrieving VIEW_YAW:
Code:
yaw = viz.get(viz.VIEW_YAW)
Alternatively, you could manually calculate the yaw based on the look vector:
Code:
import math
look = viz.get(viz.VIEW_LOOK)
euler = math.atan2(look[0],look[2]) * (180.0/math.pi)
Hope this helps.