I'm seeing this in RC7. I have a project on a cloud drive, on which I work in two different places. When I stop working on it on one of the two PC's and open it on the other, Scrivener loses the layout I had set up (editors width, basically) and I have to restore the layout from a backup. Not a big deal, but it's irritating.
Layouts are local to each machine, not a feature of the project. You can work on a project on a machine with a 4K monitor and on a small notebook … you'd need a different layout on each to be able to work on it.
The Scrivenato sometimes known as Mr X. iMac 27" (late 2015) 10.15.4, 24GB RAM, 512GB SSID MBP17" (late 2011) 10.13.6, 16GB RAM, 2TB SSID 2017 iPad, iPadOS 13.3, 128GB, Apple Pencil Scrivener, Scapple, Nisus Writer Pro, Bookends …
Actually, I thought layouts were automatically saved with the project, and the last used were selected when I open the project on the other PC - which would suit me, because I use exactly the same layout on both PC's. I saved my layout, and I select it after opening the project; but it's quite annoying doing it every time.