GPU problems at second gem location with waterfalls (mild spoilers!)

Windows 10 Pro 20H2
GPU: RTX 3800
Solasta Xbox Game Pass (18 hot fix)
Graphic Settings: Ultra, TAA, 1440p, vsync: single

Problem:
When entering the waterfall area (with the ruins) of the second gem location, my GPU spins up to 100% and the fans go crazy.
This did not happen in any other area and this did not happen in any other game so far (like Wolfenstein Youngblood, Gears 5, A way out).
Even when the game is in the background, the GOU is still sued at ~92% with high spinning fans.
When moving the screen to the cemetery area, the GPU goes down to 46%. So it's clearly the water.

This is not a problem of my GPU - you can't have something much stronger than a RTX 3080.