The issue is caused if you set the system environment variable WINEDEBUG to -all [WINEDEBUG=-all.], the proton script tests to see if it is set to -all and skips generating the steam-SteamId.log file even with the PROTON_LOG=1 variable sett in the launch options.
@kisak-valve Seems the system WINEDEBUG overrides the WINEDEBUG in the user_settings.py or proton, I don't know if thats desired or not, figured I'd let you know. I have WINEDEBUG now unset system wide.
WINEDEBUGx2 2020-10PROTON_LOG=1x2 2020-10WINEDEBUG=-all.],x1 2020-10
Proton Versions Effected: 5.0-9 and 5.9-GE-6-ST
Games Effected: Visage and Thief Simulator (There may be others but these are the two I'm working with ATM).
Issue: PROTON_LOG=1 %command% set in the [Set Launch Options] in the games mentioned Properties menu doesn't produce a steam-####.log file in $HOME or any other folder on my entire system. The game starts up and I am able to play but still no log, there are *_d3d11.log and *_d3d9.log files produced though d3d9 one is empty and both games are manually set to specific versions of proton so its not a Linux repo for the game issue.