Thanks @TenPatrol for your feedback. I don’t know if your reply was for me? 
I’m not the top #1 supporter of creating new post as it seems there’s already one. In the meantime, I may have identify one.
I think that our landing performance problem or issue that occures after a smooth flight could be related to the well-known VRAM issue or could be related to VRAM usage. This post with 600+ votes has a lot of comments and post where people suffer from landing sudden lost of fluidity. It may be usefull to support: FPS performance - VRAM bug?