If they haven’t responded yet, the first thing they told me to do is to do this:

Exit Steam entirely.

Browse to your Steam installation (Usually C:\Program Files(x86)\Steam)

Rename the “steamapps” folder to "old_steamapps"

Re-launch Steam and re-install the game.

Once the installation is complete, test the issue.

If this resolves the issue, you may copy the new files into the “old_steamapps” folder and rename it to “steamapps” to restore your other games without re-downloading.

If the issue is not resolved, you can rename the folder back to avoid having to re-install other games.

That didn’t work for me and they haven’t responded a second time so you might want to try that then mention that you have in a reply to the ticket . Good luck.