We're trying to render some oceans and are getting clearly visible buckets which are even more pronounced when denoising.
We're coming over from normally mostly rendering with Arnold so we're lacking a bit of experience on where to start debugging this problem.

Does anyone know what might be causing this? And perhaps a way around it without just throwing more samples at it as the rendertimes are already starting to creep up.

Currently we're rendering with 64 primary samples and 1/9 min/max secondary at 4k.
Scene is being lit by one HDRI, one distance light and three area lights.

Any help would be appreciated.

Cheers,
Alex

Oh dear, this looks like a bug - Do you see this with the recent daily (or production) build? There were a couple bucketing bugs in 20.5 which were fixed since release. If so, can you please submit a bug with reproducible scene so that we may investigate this ASAP? Thank you.

Ah, sorry my bad.
I forgot to write that we're still on H20.0.688 so maybe this has already been fixed in an update.