Version 2.80.4 - I have a spot lamp with volumetric lighting enabled and I've adjusted the samples and volumetric tile size to get a decent enough cone of light once the viewport finishes loading. Here's what it looks like in the viewport:
However, once I render either an opengl image or animation, it doesn't wait for all samples to load before finishing/moving on to the next frame and I get this result:
It seems to only apply a fraction of the samples to the spot lamp's volumetric light cone before finishing.
Am I missing something or is this life in pre-release 2.8?