1. yes, all workstations with water cooling at 72 degrees top temp.
2.yes, all workstations at windows 11 with recent updates
3.Yes, using tightVNC but this behavior occurs without been connected, actually for this images I only connected to take the screenshot.
4. No, I don't have other render engines installed, only corona, this is to avoid strange behavior or errors with other render engines materials that could be imported on some models, I only have vray on a laptop with 3ssmax 2022 to convert some models from vray to corona, this machine its never used to render.
5.yes, this issue is presented on several scenes, simple and heavy, with and without caustics, displacement, animated or still.
6. No, none of my workstations are set to Powe saving mode.
ill try to upload some samples, also I've notice the caustics on the preview and the final render are different and even not existent on the final render, they appear very subtle on the caustics render channel but not on the final image, here some examples.