For any future glitched runners, per https://steamcommunity.com/sharedfiles/filedetails/?id=1086279994, following the 2020/02/12 update, the Steam client will now actively prevent downloading depots with older manifests (response will be the "Manifest not available" error). One of the available workarounds is to download and use DepotDownloader - https://github.com/SteamRE/DepotDownloader/releases (requires DotNET Core install) - with the following command:

[quote]dotnet DepotDownloader.dll -app 251150 -depot 251151 -manifest 5152400201548245558 -username yourSteamUsername -password yourSteamPassword[/quote]