Your system information

• Steam client version (build number or date): Jun 17 2019, at 23:31:27
• Distribution (e.g. Ubuntu): Debian Buster
• Opted into Steam client beta?: [Yes/No] No
• Have you checked for system updates?: [Yes/No] Yes

Please describe your issue in as much detail as possible:

Describe what you expected should happen and what did happen. Please link any large code pastes as a Github Gist

Proton update should not have the "Play" button in Dowloads.

Steps for reproducing this issue:

1. wait for Proton update
2. look into Downloads when update is finished
3. Proton have the "Play" button which is generating a Steam - Error dialog by clicking on it