How are you adding the game to lutris? Are you running it through nix-ld/steam-run inside lutris? Can you share an example of a game you're trying to run?
Edit: I hadn't run a native game through Lutris in a while so I grabbed a random one to make sure it hasn't just suddenly stopped working. I downloaded a couple from GOG and each is working as expected, so this sounds like it's most likely a configuration issue, not the Lutris package itself. Make sure you have "Disable Lutris runtime" checked off and "Prefer system libraries" checked on.
