Passing a reference (pointer) to CGameID instead of CGameID appears to work. There seems to be an issue with CGameID being dereferenced in the code by steamclient.so. Probably needs to be fixed in Steam(?)
The problem can be reproduced with the native steamclient. For this it's required to take the 100 version of the SDK, and replace isteamuserstats.h with the one from 99y. Example invocation: [code] [Log with WINEDEBUG=st...
Adding a steam_api override to "Native, Builtin" has been tested and also did nothing. EDIT: See this file for reference as to what the game's using: https://github.com/ValveSoftware/Proton/blob/1e52f95633c5145aaf54bc274...