Quaternion to Rotators Singularity Threshold

I had a wierd issue in my game, debugging it lead me to an “issue” in the unreal math library:
I took a quaternion:
internal set rotation Rot 2 quat {X=0.707106352 Y=0.000000552 Z=0.707106411 W=-0.000000553}
and converted it to rotator and than back to quaternion and got:
internal set rotation Rot 2 quat to rot to quat {X=-0.000824604 Y=-0.706573904 Z=-0.000824669 W=0.707638264}

from my understanding it is caused because of the:
const float SINGULARITY_THRESHOLD = 0.4999995f;

it seems like the math library is not accurate enough to use such a big singularity threshold.
Please advise,
Ben Chen.