OSError: [Errno 22] Invalid argument: '../drive_c' with NTFS

Your system information

• Steam Runtime Version:
  0.20210817.0

• Distribution (e.g. Ubuntu 18.04):
  Manjaro Linux 21.1.3

• Full system information
  https://gist.github.com/Graphicscore/a431b91d8a3da7d8823bc9c8bee2823c

• Have you checked for system updates?
  Yes

• What compatibility tool are you using?:
  Steam Linux Runtime / Proton 6.3

• If you are using Steam Linux Runtime, or Proton 5.13 or newer: What versions are listed in SteamLinuxRuntime_soldier/VERSIONS.txt?
  Name Version Runtime Runtime_Version Comment
depot 0.20210818.24 # Overall version number
pressure-vessel 0.20210809.1
scripts v0.20210818.0-0-gc6be089 # Entry point scripts, etc.
soldier 0.20210817.0 soldier 0.20210817.0 # soldier_platform_0.20210817.0/

Please describe your issue in as much detail as possible:

If I try to run a game with proton steam will "launch" the game, nothing happens, and after a few seconds the steam client revokes the "running" status of the game. If I bypass the runtime container described in this post https://github.com/flightlessmango/MangoHud/issues/369#issuecomment-709902078 I am able to run the games.
I have tested it with FFXIV and Space Engineers.

slr-app39210-t20210918T214247.log

Steps for reproducing this issue:

1. Install a Game (eg. FFXIV or Space Engineers)
2. Try Starting the Game

Start with slr-app39210-t20210918T214247.log and reproduce the failure using Steam Linux Runtime with Proton 6.3 on NTFS, following the listed FFXIV or Space Engineers steps. Compare the behavior with the runtime bypass described in the issue. Done means the game launches through the runtime without the OSError involving '../drive_c'.