In my case almost every project I worked on for the past 6 months was like this. Lit only by couple of VRLightMtl’s. Its a mission to get low render times and clean renders. Hmmm actually its impossible. Even with pushing up the subdivs on the vraylightmtl to 128, still gives splotches and speckles
I would rise the min/max IRR rate to -3,0 (or even -3,1), and lower the HSph. subdiv back to 30. Rise the DMC image sampler to 3,7 (and lower the thresh. to 0,003). Make sure you ticked “retrace threshold” under LC (It really helps a lot). This should really clean up the render. (at the expense of render time obviously)
I would try and render the scene without IES.
But I guess the issue is solved since it was a while ago he posted.