Tiny Enemies in H4

This is a strange one, but has anyone else encountered this bug in Halo 4? I was playing spartan ops when another wave of enemies arrived like this:

On normal difficulty, just trying to complete the spartan ops challenges, then these little cockroaches show up. All of the enemies are now tiny, as are their hitboxes, and they move at full speed, which makes them appear to be going super speed for their size. They deal full damage and can take full damage.

Just a rather strange and quite funny glitch, but hopefully this is useful to someone.

Unmodded, of course.

Playing on steam with an i7 7700k and 1060 6gb