I've run into an issue with flatpaks not running through Steam on the latest beta update from yesterday, due to missing dependencies in the steam provided runtimes.

I've also seen people reporting issues with broken app images and some steam games not working since the update.

If you're on the beta and run into any strange issues, I would appreciate hearing about them, and would also recommend trying to revert to the stable update before spending too much time troubleshooting them.

Edit: steam released a update to fix "non-steam games failing to run".

Just put two and two together about my comment here about an issue launching non-steam games actually being flatpak related as those were the items I checked. Didn't spend a lot of time investigating because the programs themselves ran fine launched from the desktop, just not from the steam shortcuts so I figured steam was the problem somehow and reverted to test. No issues at all after that.

Steam released another update that seems to have fixed it, so everything should be good now.

Great to hear that, thanks!