For those of you who like to live life on the edge, the Steam Client Beta was updated yesterday with some fixes for Steam Play amongst other things.
For Steam Play, Valve fixed an issue with install scripts for Steam Play games sometimes not running correctly after you've used Big Picture Mode. Additionally, something a few people noticed with Steam Play was missing DLC, this should also now be fixed. Hopefully not long before those go in the stable client, since they can be quite troublesome issues.
The beta also updates the embedded Chromium version in Steam to Chromium 68, fixes a bug with the new Steam Chat system, allows you to rearrange Xbox controllers in the Big Picture Mode overlay and prevents Big Picture Mode quitting if a game is using its overlay.
Steam Link was also updated, to allow local multiplayer by streaming to multiple devices at the same time which sounds pretty sweet.
See the release notes here.