IsADirectoryError: trying to copy openvr_api_dxvk.dll

When I run a VR game I get a lot of the tracebacks in my logs.
I have no idea if they are serious or not, but I couldn't find any info about them:

Traceback (most recent call last):
  File "/home/user/.local/share/Steam/steamapps/common/Proton 4.11/proton", line 709, in <module>
    g_session.init_session()
  File "/home/user/.local/share/Steam/steamapps/common/Proton 4.11/proton", line 552, in init_session
    g_compatdata.setup_prefix()
  File "/home/user/.local/share/Steam/steamapps/common/Proton 4.11/proton", line 334, in setup_prefix
    try_copy(g_proton.lib_dir + "wine/dxvk/openvr_api_dxvk.dll", self.prefix_dir + "/drive_c/windows/syswow64/")
  File "/home/user/.local/share/Steam/steamapps/common/Proton 4.11/proton", line 61, in try_copy
    shutil.copy(src, dst)
  File "/usr/lib/python3.7/shutil.py", line 248, in copy
    copyfile(src, dst, follow_symlinks=follow_symlinks)
  File "/usr/lib/python3.7/shutil.py", line 121, in copyfile
    with open(dst, 'wb') as fdst:
IsADirectoryError: [Errno 21] Is a directory: '/home/user/SteamLibrary/steamapps/compatdata/620980/pfx//drive_c/windows/syswow64/'

It is indeed true that syswow64 is a directory...
I guess the openvr_api_dxvk.dll should be copied into this directory..?

BTW the openvr_api_dxvk.dll (somehow) managed to live in this directory/location (already)...

Start at the setup_prefix call on line 334 and try_copy in the proton script at line 61, then reproduce the VR-game launch to inspect the traceback. Check the handling of openvr_api_dxvk.dll when the destination is the syswow64 directory. Done means the launch no longer reports IsADirectoryError and the DLL is placed in that directory.