BATTLETECH - Backer Assets not being installed from Steam

[Shipwreck]

One line summary of your issue
Backer Assets not being installed from Steam

What platform are you running the game on?
Steam

What operating system do you use?
Windows 10

Which version of the game are you running?
Latest

What DLC do you have installed?
Flashpoint, Urban Warfare, Shadowhawk Pack, Heavy Metal

Please explain your issue is in as much detail as possible.
Game locks up when trying to select any Valhala paint scheme. Error log states that the appropriate "chrprfmech" for backer paint schemes are missing.

Have you tried verifying your files?
Yes

Steps to reproduce the issue
Select any of the backer paint scheme mechs.

Attach DxDiag (PC), System Info log (Mac), or run sudo lshw -html > specs.html and uploaded specs.html (Linux)
File(s) attached

Attach Output Log
Windows: \Users\YourUserName\AppData\LocalLow\Harebrained Schemes\BATTLETECH\output_log.txt
Mac OS: Users >{name} > Library > Logs > Unity > Player.log
Linux: ~/.config/unity3d/Harebrained Schemes/BATTLETECH/Player.log
File(s) attached

If the game crashed, please attach the crash file with the time stamp closest to the crash.
Windows: [Steam library folder]\steamapps\common\BATTLETECH\DumpBox
For v.17 and beyond try here: C:\Users\[YourUserName]\AppData\LocalLow\Harebrained Schemes\BATTLETECH
OSX: Macintosh HD > Users > [username] > Library > Application Support > Steam > steamapps > common > BattleTech > DumpBox
Linux: [Steam library folder]/steamapps/common/BATTLETECH/DumpBox
File(s) attached

If a save game was loaded at the start of the game session, upload it. Please make sure to upload the save game with the timestamp closest to when you loaded it.
Windows:
Steam: [Steam installation folder]\userdata[SteamID]\637090\remote\C0\SGS1
GOG: 'C:\Users\USER_ID\AppData\Local\GOG.com\Galaxy\Applications\50593543263669699\Storage\Shared\Files\C#\SGS#'
Vanilla:'C:\Users\USER_ID\AppData\LocalLow\Harebrained Schemes\BattleTech\C#\SGS#'
OSX:
Steam: Macintosh HD > Users > [username] > Library > Application Support > Steam > userdata > [SteamID] > 637090 > remote > C#> SGS#
GOG: Macintosh HD > Users > [username] > Library > Application Support > GOG.com > Galaxy > Applications > 50593543263669699 > Storage > Shared > Files > C# > SGS#
Vanilla: Macintosh HD > Users > [username]> Library > Application Support > unity.Harebrained Schemes.BattleTech > C# > SGG#
Linux:
Steam: /home/.steam/steam/userdata/[steamID]/637090/remote/C#/SGS#
GOG: /home/[username]/.config/unity3d/Harebrained Schemes/BATTLETECH/remote/C#/SGS#/
Vanilla: /home/[username]/.config/unity3d/Harebrained Schemes/BATTLETECH/remote/C#/SGS#/
File(s) attached

Attach screenshot / video
File(s) attached

 

[AndrewT]

Unable to open archive file: F:/SteamLibrary/steamapps/common/BATTLETECH/BattleTech_Data/StreamingAssets/data/assetbundles/chrprfmech_thunderboltbacker-valha

I don't have that file either, but then again I'm not a backer of course. I assume that file is indeed physically missing for you?

And, has this ever worked for you? Because if so, it is hard to see how the file could have just vanished.