I am happy to announce that the problem has been solved. After trying to reproduce the problem in a clean project, I noticed the flickering issue appeared when a Texture2D had “Virtual Texture Streaming” parameter checked (when used in landscape material, even if the texture with this parameter was used after sampling the RVT). So I batch unchecked that checkbox on every texture used in the level and the issue no longer persists. Not sure if it is a bug or limitation. Thank you everyone for the help
