Blotches / splotches - indirect lighting reflecting too strongly

Hiya - I hope it’s OK to post technical questions here.

So here’s a render I did as an exercise (after the amazing Photographer Todd Hido). You can see on the landscape floor, where various items are touching, there are some blotches and splotches.

I think they are related to the indirect lighting value of the direct light - turning that down reduces the glowing halo. However, I need that lighting in my scene.

I think it’s also related to Lumen raytracing and Lumen.

I know there are a 100 things to look att - but I wondered if anyone had seen this before.

The snow is a snow material from megascans, and the twigs are too.

Has anyone encountered this before?

image