If I Select Per- user on my second, Windows 10 Account. Vortex signs in to my Nexus Profile and shows only one managed game "Stardew Valley". It is empty. No mods, no other games managed. Nothing. I don't know why selecting per-user would log me into my account, but it happens every time.
Perhaps the one ,managed game, is trying to pull files from the main account to run. Causing an issue? I don't see why that would completely break one instance of the software but who knows.