I found a solution.
I set Proton-5.8-GE-2-MF as a Steam Play compatibility tool on May 19 2020.
I uninstalled the game a few days later but the option stayed set.
Then I deleted Proton-5.8-GE-2-MF directory from ~/.steam/steam/compatibilitytools.d/.
Today when I had a problem with opening properties I made ~/.steam/steam/compatibilitytools.d/ directory empty by removing Proton-5.9-GE-2-MF that I had there.
Then I restarted Steam and opening properties of the game started to work.
This case should be handled by Steam to prevent crashes.
proton 5.8-ge-2x1 2020-07proton 5.9-ge-2x1 2020-07
Your system information
Jun 4 2020, at 05:51:01, steam-runtime_0.20200505.0Ubuntu 20.04 LTSBeta Jun 30 2020, at 04:15:14is also affectedPlease describe your issue in as much detail as possible:
Steam crashes/closes when I try to open properties of the
GWENT: The Witcher Card Game.Other games in my library aren't affected by this issue.
When I created the report https://github.com/ValveSoftware/Proton/issues/3890 on May 19 2020 I used steam-runtime_0.20200417.0 and then this issue didn't exist so it is a regression.
Steps for reproducing this issue:
GWENT: The Witcher Card Game