get_rotation()[2] means left rotation of head is not working properly as compared to right side head rotation.

[akhirai560]

The get_rotation()[2] does not change properly and is always in between 0.0 to 0.15.
Compared to that get_rotation()[1] right side rotation is between 0.1 to 0.6 .

[xavierjs]

get_rotation() provides Euler's angle; get_rotation()[2] and get_rotation()[1] are rotation around different axis