Smudge or cloud like shadows on render

Does anybody know how to fix those smudge shadows shown on the picture? Or maybe someone knows what’s causing them?
Thanks in advance!

Wow. You actually managed to offer zero relevant information…
Up to this point we don’t even know which render engine this is. My guess: Denoiser on a render with too few samples?

It could be using AO with Cycles, which isn’t necessary.

It’s definitely the denoiser being used with too few samples, as BI doesn’t have anything that could create a splotchy image.

For a recent scene, I used Branched Path Tracing with the denoise radius at 10 and feature weights at 0.05 and 0.4 respectively (0.4 is the neighbor weight value for reference). Worked very well.

I’d concur with denoiser + too few samples.

Yea,it was Cycles with low samples + denoiser that caused these shadows.
Thanks for the help!