Particles are no longer lit after going from Forward Renderer back to Deferred

Title of the post says it all really. I rolled back my renderer ‘from’ forward to deferred so that I could check differences in look and performance. Now none of my translucent (default lit) particles are being lit by any light source. I’ve tried resetting my DerivedDataCache and recompiling all the shaders, didn’t work.

I’ve migrated the Particle Systems into a new project with the renderer set to deferred and they exhibit the same lack of lighting. Is there some hidden setting that switches in the material or particle system when it’s in a different renderer?