I had this flickering issue for such a long time but haven't got to ask or find the solution on my own.

When trying to make the camera smooth its position movement it makes the object, usually the Player object which the camera attached to start flickering when moving, if that makes sense.

Easily reproduce with Camera Collision tutorial by changing this line

desired_camera.at =Players[0].ctrl.center();

to

AdjustValTime(desired_camera.at, Players[0].ctrl.center(), 0.001);

moving with strafe is most noticeable.

Any insight on how to fix this? possibly with both motion blur on and off.

inside Init(), you can do
if(int freq=D.freq())Physics.precision(freq);else Physics.timestep(PHYS_TIMESTEP_VARIABLE);

or just:
Physics.timestep(PHYS_TIMESTEP_VARIABLE);

Just an example.

Thank you, I wouldn't have thought it was related to Physics.