TF2 Particles are Dysfunctional

As of update 159, all of my TF2 particle systems have ceased functioning, when a precache or use is requested it states that the particle system is unknown.

Any ideas what’s up? Is it a TF2 update or a GMod update that’s caused this?

I’m leaning toward the latter since the last TF2 update was 2 days ago and made no mention of particles in the changelog.